I seriously doubt that more than half the Pilots in the UK even bother to keep track of their Licence/Rating validity any more, or that the CAA could successfully prosecute anyone for having an invalid Licence/Rating.
MJ,
I'm not sure I totally agree with that, but you might be right about the latter.
Personally, I feel the need to satisfy a far more onerous body than our regulator, namely the insurance company. Believe me, they go through validity with a fine-tooth comb. For this reason, I keep a meticulous record of all flights I'm responsible for.
TOO