The Query was for 500 caches, I think. I checked Trad,Multi-cache and Letterbox hybrid,Any container, caches That I haven't found,Are Available to All Users and Is Enabled.I didn't specify Difficulty or Terrain and set My Location as the origin of the search.
Your point about Within 100 km may be the problem - I set Within 100 miles (oops).
If I repeat the Query setting it for 30 miles, won't that lead to downloading a load of duplicates? Will my GPSr reject the dupes?