Just to add something to this Flat Earther's, 'Who's working the traffic' debate...
I was on a flight over N.Wales working and Squawking Valley Radar. I turned onto 120deg and dropped behind the Snowdonian range, and continued for another 40nm, still tuned into Valley. I was then within range of Shawbury AIAA, but could get no reply from them as well, because they had packed in for the day.
So I was in an area where I could have worked up to 4 different agencies, and squawking one that was 60nm away, and most likely gone home as well.
Fortunately Shawbury area is not really an AIAA at that time of day.