diff --git a/core/forms.py b/core/forms.py
index 24beee4..5cbbe95 100644
--- a/core/forms.py
+++ b/core/forms.py
@@ -208,7 +208,9 @@ class EntranceLetterForm(ModelForm):
     Nb. The relationship between caves and entrances has historically been a many to many relationship.
     With entrances gaining new caves and letters when caves are joined.
     """
-    entranceletter = forms.CharField(required=False, widget=forms.TextInput(attrs={"size": "2"}))
+    
+    # This only needs to be required=True for the second and subsequent entrances, not the first. Tricky.
+    entranceletter = forms.CharField(required=True, widget=forms.TextInput(attrs={"size": "2"}))
 
     class Meta:
         model = CaveAndEntrance
diff --git a/core/views/caves.py b/core/views/caves.py
index c845f01..adb3398 100644
--- a/core/views/caves.py
+++ b/core/views/caves.py
@@ -519,7 +519,7 @@ def edit_entrance(request, path="", caveslug=None, entslug=None):
                 entranceletter = entletterform.cleaned_data["entranceletter"]
             else:
                 print(f"- POST INVALID {caveslug=} {entslug=} {path=} entletterform invalid.")
-                return render(request, "errors/badslug.html", {"entletter problem in edit_entrances()"})
+                return render(request, "errors/badslug.html", {"badslug": "entletter problem in edit_entrances()"})
         # if entform.is_valid() and entletterform.is_valid():
         if entform.is_valid():
             entrance = entform.save(commit=False)
diff --git a/parsers/locations.py b/parsers/locations.py
index 92df13e..d3d65ab 100644
--- a/parsers/locations.py
+++ b/parsers/locations.py
@@ -292,7 +292,7 @@ def LoadPositions():
             print(message)
 
     topdata = os.fspath(Path(settings.SURVEX_DATA) / settings.SURVEX_TOPNAME)
-    print(f" - Generating a list of Pos from {topdata}.svx and then loading...")
+    print(f" - Generating a list of Pos from {topdata}.3d and then loading...")
 
     found = 0
     print("\n")  # extra line because cavern overwrites the text buffer somehow
@@ -316,7 +316,7 @@ def LoadPositions():
         runcavern3d()
     if not os.path.isfile(d3dpath):
         runcavern3d()
-    elif d3d_t - svx_t > 0:  # stale, 3d older than svx file
+    elif d3d_t - svx_t > 0:  # stale, 3d older than svx file 
         runcavern3d()
     elif now - d3d_t > 24 * 60 * 60:  # >1 days old, re-run anyway
         runcavern3d()
@@ -341,62 +341,54 @@ def LoadPositions():
         stash_data_issue(parser="positions", message=message, url=f"/entrance_data/{pospath}_edit")
         print(message)
         return
+    with open(pospath) as posfile:
+        posfile.readline()  # Drop header
+        
+        sbdict = {}
+        dups = 0
+        lineno = 1 # we dropped the header
+        for line in posfile.readlines():
+            lineno += 1
+            r = poslineregex.match(line)
+            if r:
+                x, y, z, sbid = r.groups() # renamed id to sbid so as to not confuse with Django internal .id
+                if sbid in sbdict:
+                    dups += 1
+                    message = f" ! DUPLICATE SurvexBlock identifier in .pos file '{sbid}'\n{sbs[sbid]}\n{lineno} / {line}"
+                    print(message)
+                    stash_data_issue(parser="positions", message=message)
+                else:
+                    sbdict[sbid] = lineno
+     
 
-    posfile = open(pospath)
-    posfile.readline()  # Drop header
-    
-    sbdict = {}
-    dups = 0
-    lineno = 1 # we dropped the header
-    for line in posfile.readlines():
-        lineno += 1
-        r = poslineregex.match(line)
-        if r:
-            x, y, z, sbid = r.groups() # renamed id to sbid so as to not confuse with Django internal .id
-            if sbid in sbdict:
-                dups += 1
-                message = f" ! DUPLICATE SurvexBlock identifier in .pos file '{sbid}'\n{sbs[sbid]}\n{lineno} / {line}"
-                print(message)
-                stash_data_issue(parser="positions", message=message)
-            else:
-                sbdict[sbid] = lineno
- 
-
-            for sid in mappoints:
-                if not sid: # catch None entry
-                    continue
-                if sbid.endswith(sid) or sbid.endswith(sid.lower()):
-                    blockpath = "." + sbid[: -len(sid)].strip(".") # only the most recent one that is mappoints
-                    if sid in found_points:
-                        found_points[sid] += 1
-                    else:
-                        found_points[sid] = 1
-                   
-                    try:
-                        ss = SurvexStation(name=sbid)
-                        ss.x = float(x)
-                        ss.y = float(y)
-                        ss.z = float(z)
-                        ss.entrance = mappoints[sid]
-                        ss.save()
-                        found += 1
-                    except:
-                        message = f" ! {lineno} FAIL to create SurvexStation Entrance point {blockpath} {sid}"
-                        print(message)
-                        stash_data_issue(parser="positions", message=message)
-                        store_data_issues()
-                        raise
+                for sid in mappoints:
+                    if not sid: # catch None entry
+                        continue
+                    if sbid.endswith(sid) or sbid.endswith(sid.lower()):
+                        blockpath = "." + sbid[: -len(sid)].strip(".") # only the most recent one that is mappoints
+                        if sid in found_points:
+                            found_points[sid] += 1
+                        else:
+                            found_points[sid] = 1
+                       
+                        try:
+                            ss = SurvexStation(name=sbid)
+                            ss.x = float(x)
+                            ss.y = float(y)
+                            ss.z = float(z)
+                            ss.entrance = mappoints[sid]
+                            ss.save()
+                            found += 1
+                        except:
+                            message = f" ! {lineno} FAIL to create SurvexStation Entrance point {blockpath} {sid}"
+                            print(message)
+                            stash_data_issue(parser="positions", message=message)
+                            store_data_issues()
+                            raise
     validate_entrance_stations() # do not need to use db here really
     positions_filename = Path(pospath).name
     print(f" -  {found} distinct SurvexStation entrance stations identified in {lineno:,} lines in {positions_filename}.")
     if dups > 0:
         print(f" -  {dups} Duplicated SurvexStation entrances found")
-        
-    # for p in mappoints:
-        # if p not in found_points:
-            # print(f"Valid point {p} NOT found in {positions_filename}")
-    # print(f" -  {len(mappoints)} mappoints,   {len(found_points)} found_points")
-    # for sid in found_points:
-        # if found_points[sid] > 1:
-            # print(f" -  {sid} - {found_points[sid]}")
+     
     store_data_issues()