attempted speedup, explicit dates wallet objects

parsers/survex.py

@@ -660,6 +660,8 @@ class LoadingSurvex():
             else:
                 survexblock.scanswallet = manywallets[0] # this is a ForeignKey field
                 survexblock.save()
+                # This is where we should check that the wallet JSON contains a link to the survexfile
+                # and that the JSON date and walletdate are set correctly to the survexblock date.
         else:
             perps = get_people_on_trip(survexblock)
             message = f" ! Wallet *REF bad in '{survexblock.survexfile.path}' '{refscan}' NOT in database i.e. wallet does not exist {perps}."