Totally irrelevant
Not very relevant either:
Numerous people have an UK CAA license and fly/live in other parts of Europe (like myself), since they got theirs in the US through one of the JAA flight schools.
In that case the number of 15000-20000 UK PPLś is rather low.
EASA (a JAA school formerly Ormond beach flight school) is claiming that they trained over 10000 pilots since 1991 (probably most of them JAA).
btw: I didn do my training with them