As far as I know, my eyesight is perfectly corrected and would now be accepted for a JAA class 1 medical.
I actually had my last class 2 at the CAA medical centre at Gatwick - and this is a sort of a cheap way to get a view on your chances of a class 1 - just ask the medical officer if he thinks if you would pass or not . Clearly this won't give you the extra tests but it's a start.
I think £400 is not really a barrier - you can think of it as a healthcheck anyway and the follow-on costs are far more.
You're right in that I could probably get another job in IT (although it's notoriously ageist) - but if I was the kind of person who took major leaps of faith then I wouldn't be asking these questions now anyway.