diff --git a/cave_data/1623-Rentner-Express.html b/cave_data/1623-rentner.html
similarity index 88%
rename from cave_data/1623-Rentner-Express.html
rename to cave_data/1623-rentner.html
index cd453f6f1..848513c07 100644
--- a/cave_data/1623-Rentner-Express.html
+++ b/cave_data/1623-rentner.html
@@ -17,8 +17,8 @@ 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>1623-Rentner-Express</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-->
+<caveslug>1623-rentner</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>Rentner-Express</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'
 code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast.htm
@@ -36,11 +36,10 @@ code used in the Austrian kataster e.g '1/S +' - https://expo/.survex.com/katast
     +   erforscht (exploration considered complete)
  -->
 <kataster_number></kataster_number> <!-- (Either this or unofficial_number is required). Official number in Austrian kataster if one has been allocated  -->
-<unofficial_number>Rentner-Express</unofficial_number><!-- (Either this or kataster_number is required). Initial temporary cave ID used until kataster number is allocated e.g. '2012-DD-01'-->
+<unofficial_number>rentner</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>1623-RENTNER</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 -->
-  <!-- DEBUG  1623-RENTNER+1623-RENTNER 'Z' == -->
+  <entranceslug>1623-rentner</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/1626-casino.html b/cave_data/1626-casino.html
index 83b10a607..9c0551526 100644
--- a/cave_data/1626-casino.html
+++ b/cave_data/1626-casino.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>1626-CASINO</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>1626-casino</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>1626</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/1626-upside-down.html b/cave_data/1626-upside-down.html
index e2d8893e5..e03adea84 100644
--- a/cave_data/1626-upside-down.html
+++ b/cave_data/1626-upside-down.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>1626-UPSIDE-DOWN</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>1626-upside-down</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>1626</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/entrance_data/1623-RENTNER.html b/entrance_data/1623-rentner.html
similarity index 97%
rename from entrance_data/1623-RENTNER.html
rename to entrance_data/1623-rentner.html
index 59c400bf7..4e90122c8 100644
--- a/entrance_data/1623-RENTNER.html
+++ b/entrance_data/1623-rentner.html
@@ -19,7 +19,7 @@ though, you do not need to do a data import as it happens automatically -->
 <br>
 <entrance>
 <non_public>False</non_public>
-<slug>1623-RENTNER</slug> <!-- one entrance and one slug per entrance_data file -->
+<slug>1623-rentner</slug> <!-- one entrance and one slug per entrance_data file -->
 <name></name>
 <entrance_description></entrance_description>
 <explorers></explorers>