diff --git a/cave_data/2012-ns-01.html b/cave_data/1623-2012-ns-01.html
similarity index 92%
rename from cave_data/2012-ns-01.html
rename to cave_data/1623-2012-ns-01.html
index 07bd5a444..0313cc307 100644
--- a/cave_data/2012-ns-01.html
+++ b/cave_data/1623-2012-ns-01.html
@@ -10,7 +10,7 @@
 <body>
 <cave>
 <non_public>False</non_public><!-- 'False' or 'True'. True if the cave should only be visible to logged-in users. Caves are normally public, so enter 'False' unless you know otherwise. -->
-<caveslug>2012-ns-01</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
+<caveslug>1623-2012-ns-01</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
 <official_name></official_name><!-- Name of the cave (normally in German)  Use &uuml; for u+Umlaut and &ouml; for o+umlaut eg H&ouml;hle for Hohle and Gl&uuml;ck for Gluck-->
 <area>1623</area><!-- the CUCC-defined areas shown in http://expo.survex.com/areas.htm -->
 <kataster_code></kataster_code><!-- 'length-or-depth/type exploration'
@@ -32,7 +32,7 @@ code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast
 <unofficial_number>2012-ns-01</unofficial_number><!-- (Either this or kataster_number is required). Initial temporary cave ID used until kataster number is allocated e.g. '2012-DD-01'-->
 
 <entrance>
-  <entranceslug>2012-ns-01</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
+  <entranceslug>1623-2012-ns-01</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
   <letter></letter><!--Leave blank for single-entrance cave. If there is more than one entrace then the letter needs to be given. Generally matches the entranceslug ID.  -->
 </entrance>
 
diff --git a/cave_data/2012-ns-02.html b/cave_data/1623-2012-ns-02.html
similarity index 92%
rename from cave_data/2012-ns-02.html
rename to cave_data/1623-2012-ns-02.html
index ca1b117d5..a0ecf709e 100644
--- a/cave_data/2012-ns-02.html
+++ b/cave_data/1623-2012-ns-02.html
@@ -10,7 +10,7 @@
 <body>
 <cave>
 <non_public>False</non_public><!-- 'False' or 'True'. True if the cave should only be visible to logged-in users. Caves are normally public, so enter 'False' unless you know otherwise. -->
-<caveslug>2012-ns-02</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
+<caveslug>1623-2012-ns-02</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
 <official_name></official_name><!-- Name of the cave (normally in German)  Use &uuml; for u+Umlaut and &ouml; for o+umlaut eg H&ouml;hle for Hohle and Gl&uuml;ck for Gluck-->
 <area>1623</area><!-- the CUCC-defined areas shown in http://expo.survex.com/areas.htm -->
 <kataster_code></kataster_code><!-- 'length-or-depth/type exploration'
@@ -32,7 +32,7 @@ code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast
 <unofficial_number>2012-ns-02</unofficial_number><!-- (Either this or kataster_number is required). Initial temporary cave ID used until kataster number is allocated e.g. '2012-DD-01'-->
 
 <entrance>
-  <entranceslug>2012-ns-02</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
+  <entranceslug>1623-2012-ns-02</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
   <letter></letter><!--Leave blank for single-entrance cave. If there is more than one entrace then the letter needs to be given. Generally matches the entranceslug ID.  -->
 </entrance>
 
diff --git a/cave_data/2012-ns-05.html b/cave_data/1623-2012-ns-05.html
similarity index 92%
rename from cave_data/2012-ns-05.html
rename to cave_data/1623-2012-ns-05.html
index 8dde4ef12..53107cd2a 100644
--- a/cave_data/2012-ns-05.html
+++ b/cave_data/1623-2012-ns-05.html
@@ -10,7 +10,7 @@
 <body>
 <cave>
 <non_public>False</non_public><!-- 'False' or 'True'. True if the cave should only be visible to logged-in users. Caves are normally public, so enter 'False' unless you know otherwise. -->
-<caveslug>2012-ns-05</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
+<caveslug>1623-2012-ns-05</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
 <official_name></official_name><!-- Name of the cave (normally in German)  Use &uuml; for u+Umlaut and &ouml; for o+umlaut eg H&ouml;hle for Hohle and Gl&uuml;ck for Gluck-->
 <area>1623</area><!-- the CUCC-defined areas shown in http://expo.survex.com/areas.htm -->
 <kataster_code></kataster_code><!-- 'length-or-depth/type exploration'
@@ -32,7 +32,7 @@ code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast
 <unofficial_number>2012-ns-05</unofficial_number><!-- (Either this or kataster_number is required). Initial temporary cave ID used until kataster number is allocated e.g. '2012-DD-01'-->
 
 <entrance>
-  <entranceslug>2012-ns-05</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
+  <entranceslug>1623-2012-ns-05</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
   <letter></letter><!--Leave blank for single-entrance cave. If there is more than one entrace then the letter needs to be given. Generally matches the entranceslug ID.  -->
 </entrance>
 
diff --git a/cave_data/1623-2012-ns-06.html b/cave_data/1623-2012-ns-06.html
index 4654b70aa..e0da97cc6 100644
--- a/cave_data/1623-2012-ns-06.html
+++ b/cave_data/1623-2012-ns-06.html
@@ -10,7 +10,7 @@
 <body>
 <cave>
 <non_public>False</non_public><!-- 'False' or 'True'. True if the cave should only be visible to logged-in users. Caves are normally public, so enter 'False' unless you know otherwise. -->
-<caveslug>2012-ns-06</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
+<caveslug>1623-2012-ns-06</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
 <official_name></official_name><!-- Name of the cave (normally in German)  Use &uuml; for u+Umlaut and &ouml; for o+umlaut eg H&ouml;hle for Hohle and Gl&uuml;ck for Gluck-->
 <area>1623</area><!-- the CUCC-defined areas shown in http://expo.survex.com/areas.htm -->
 <kataster_code></kataster_code><!-- 'length-or-depth/type exploration'
@@ -32,7 +32,7 @@ code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast
 <unofficial_number>2012-ns-06</unofficial_number><!-- (Either this or kataster_number is required). Initial temporary cave ID used until kataster number is allocated e.g. '2012-DD-01'-->
 
 <entrance>
-  <entranceslug>2012-ns-06</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
+  <entranceslug>1623-2012-ns-06</entranceslug><!-- Internal ID to refer to each entrance instance in the entrance files (typically the same as that filename (e.g. 1623-161c). Matches the 'slug' field in the entrance file -->
   <letter></letter><!--Leave blank for single-entrance cave. If there is more than one entrace then the letter needs to be given. Generally matches the entranceslug ID.  -->
 </entrance>
 
diff --git a/cave_data/1623-2012-ns-07.html b/cave_data/1623-2012-ns-07.html
index 7d5d86a3c..c77ac8f25 100644
--- a/cave_data/1623-2012-ns-07.html
+++ b/cave_data/1623-2012-ns-07.html
@@ -17,7 +17,7 @@ the form documented at
 
 <cave>
 <non_public>False</non_public><!-- 'False' or 'True'. True if the cave should only be visible to logged-in users. Caves are normally public, so enter 'False' unless you know otherwise. -->
-<caveslug>2012-ns-07</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
+<caveslug>1623-2012-ns-07</caveslug><!--(Required). Internal I.D. used to refer to this cave in entrance data files. Typically the same as the filebase, e.g. '1623-195'  -->
 <official_name></official_name><!-- Name of the cave (normally in German)  Use &uuml; for u+Umlaut and &ouml; for o+umlaut eg H&ouml;hle for Hohle and Gl&uuml;ck for Gluck-->
 <area>1623</area><!-- the CUCC-defined areas shown in http://expo.survex.com/areas.htm -->
 <kataster_code></kataster_code><!-- 'length-or-depth/type exploration'
diff --git a/cave_data/pendingcaves.txt b/cave_data/pendingcaves.txt
index 25a0886fc..c9b221a76 100644
--- a/cave_data/pendingcaves.txt
+++ b/cave_data/pendingcaves.txt
@@ -5,7 +5,6 @@
 1623-2012-ft-01
 1623-2012-ft-02
 1623-2012-ns-05 
-1623-2012-ns-05 
 1623-2013-CUCC-02
 1623-2013-CUCC-03
 1623-2017-21
diff --git a/entrance_data/2012-ns-01.html b/entrance_data/1623-2012-ns-01.html
similarity index 98%
rename from entrance_data/2012-ns-01.html
rename to entrance_data/1623-2012-ns-01.html
index 4b5e3cfac..83a10ae7c 100644
--- a/entrance_data/2012-ns-01.html
+++ b/entrance_data/1623-2012-ns-01.html
@@ -14,7 +14,7 @@
 <body>
 <entrance>
 <non_public>False</non_public>
-<slug>2012-ns-01</slug>
+<slug>1623-2012-ns-01</slug>
 <name></name>
 <entrance_description></entrance_description>
 <explorers></explorers>
diff --git a/entrance_data/2012-ns-02.html b/entrance_data/1623-2012-ns-02.html
similarity index 98%
rename from entrance_data/2012-ns-02.html
rename to entrance_data/1623-2012-ns-02.html
index 7fe5c566b..1cf991d71 100644
--- a/entrance_data/2012-ns-02.html
+++ b/entrance_data/1623-2012-ns-02.html
@@ -14,7 +14,7 @@
 <body>
 <entrance>
 <non_public>False</non_public>
-<slug>2012-ns-02</slug>
+<slug>1623-2012-ns-02</slug>
 <name></name>
 <entrance_description>Noel did not record any location or description.</entrance_description>
 <explorers>Noel Snape</explorers>
diff --git a/entrance_data/2012-ns-05.html b/entrance_data/1623-2012-ns-05.html
similarity index 98%
rename from entrance_data/2012-ns-05.html
rename to entrance_data/1623-2012-ns-05.html
index c51814135..3031a07fd 100644
--- a/entrance_data/2012-ns-05.html
+++ b/entrance_data/1623-2012-ns-05.html
@@ -14,7 +14,7 @@
 <body>
 <entrance>
 <non_public>False</non_public>
-<slug>2012-ns-05</slug>
+<slug>1623-2012-ns-05</slug>
 <name></name>
 <entrance_description></entrance_description>
 <explorers></explorers>
diff --git a/entrance_data/2012-ns-06.html b/entrance_data/1623-2012-ns-06.html
similarity index 98%
rename from entrance_data/2012-ns-06.html
rename to entrance_data/1623-2012-ns-06.html
index 56cbc8534..f0fe9b130 100644
--- a/entrance_data/2012-ns-06.html
+++ b/entrance_data/1623-2012-ns-06.html
@@ -14,7 +14,7 @@
 <body>
 <entrance>
 <non_public>False</non_public>
-<slug>2012-ns-06</slug>
+<slug>1623-2012-ns-06</slug>
 <name></name>
 <entrance_description></entrance_description>
 <explorers></explorers>
