I have never quite understood how this works for a VFR flightplan from say France to a private strip. Clearly the French won't receive an arrival message unless you call some local atsu and get them to send it (which no one seems to do) the French won't know if you have arrived. I have never heard of an issue with the French searching for planes returning to the UK so assume they must ignore unclosed plans to Brittain.
That's a very good point.
After a farm strip departure, you are supposed to do one of the following
1. Get somebody with an Afpex account (they can use yours
) to issue a DEP message
2. Get the local FIS unit to issue the DEP message
3. Do it yourself, with a satellite phone internet connection and running Afpex
As you say, I am sure the French just ignore UK inbound flight plans, and perhaps too few people depart UK farm strips for say Germany.