Don't confuse the BA medical exam on your initial application for a job, with the routine licence medical you will undergo every six months once selected.
The routine aircrew licence medical is to JAA standard (and no more) as Diesel has said. You can even pick which AME you go and see. The doctor will examine you, on behalf of the JAA, to assess whether you will still be fit to fly in six months time.
The initial exam is to a much higher standard, in just about every respect.
Why? Because the AME is now examining you, on behalf of BA, to assess, as best he can, if you will still be fit to fly in 35 years time, and whether you may have a lot of time off sick during your career.
Staff sickness is a hot topic in BA at the moment, so don't expect the initial standard to be lowered when BA start recruiting again.
BA has the jobs, and can set the initial medical standard as high as it likes. If you can't pass it, there are hundreds out there who can and will.
Due to a medical condition, I found out that I'm not one of them, but that's life! I'll try again in a couple of years.
No use moaning about it, and be careful what you say on interview, because BA are very sensitive to "attitude" during selection.
Good luck when they start recruiting again.