It was the case, a few years back, that BA captains had to retire from the left seat at 55, but could continue as SFOs until 60; has this now stopped?
Not sure how widespread that ever was - as far as I recall it was done very very briefly for reasons I can no longer remember on the 744 a while back (I'm talking mid '90s). It certainly didn't ever become the "norm" across the company.