I very much doubt there'll be a published age limit, in line with Aer Lingus (?), but the reality may be different and hence I don't expect many successful 50 year olds.
Fair play to BA for reintroducing this scheme, despite what seems to be a huge number of newly qualifieds around. I wonder if they're having problems with getting people of the right fit?
Interesting... perhaps Ireland does not have the same age discrimination laws that the UK has. An age limit is totally illegal in the UK, in fact asking your age in an interview is illegal (just like "are you pregnant") and must be approached with the utmost care and for a very valid reason.