Thanks for the responses.
As I said, I don't have a major issue of principle over the Class A, just a feeling that it's something of a hammer to crack a nut. It's interesting to see the movement numbers, and in principle that might justify Class A, but my feeling is that it can't be worse than MAN or LHR and even there the Class A is stepped and not just a blanket covering. Sure there are 737s, but not at sea level or for that matter at 5000' by ORTAC. Basically, I just can't see how it can be justified in aviation terms (as opposed to political terms).
Mark - thanks for the thread link. I know how annoying it can be for the same topics to be replayed. I did search before posting, but clearly used the wrong terms as it didn't show up this posting. It's certainly interesting and seems to confirm the view that it is largely historic, designed in part to keep French military under control and it suits the Islands - whatever its current justification (or not) in aviation safety terms.
Thanks everyone for your helpful replies; I am now better informed.
24R