As far as I can see the BA medical is tougher as they take a more long term view - they want people who are still going to be medically fit at 50 odd as opposed to the CAA who IMHO just seem to want to check that you can see enough to not bump into anyone else and are not about to drop dead at the controls.
BA will focus on ailments that could worsen over time - probably why their eyesight test is harder.
Great posting WWW - I passed the selection in October and you are spot on.
While we took the group exercise seriously, we still managed to have a laugh. Don't underestimate the power of the HR person - it's a more relaxed interview but don't let this make you take it less seriously.
Anyone with the interviews coming up, all the very best. May the force be with you young jedi knights!!