Fix some dodgy handling of DME references

core/sig_lookup_helper.py

@@ -1,4 +1,5 @@
 import logging
+import re
 
 from pyhamtools.locator import latlong_to_locator, locator_to_latlong
 
@@ -41,9 +42,12 @@ def get_sig_ref_info(sig_name, ref_id):
         ### FUDGES ###
         #
         # DME fudge. Our database has leading zeros padding to 5 digits which is the expected format, but not all
-        # activators add leading zeros.
+        # activators add leading zeros. We also need to normalise "DME 01234" to "DME-01234" to match what's in our
+        # database.
         if sig_name.upper() == "DME":
-            ref_id = ref_id.zfill(5)
+            match = re.match(r"DME[\- ]\d{3,5}", ref_id, re.IGNORECASE)
+            number = match.group(1)
+            return f"DME-{number.zfill(5)}"
 
         # DTMBA spotters sometimes include spaces and dashes, our regex allows them but they must be removed here so we
         # can look up against the official list which doesn't have them