I was talking about this issue to a Union rep a couple of days ago and his take was that to have a compulsory retirement age less than the state pensionable age contravenes current EU age discrimination laws and was open to legal challenge. IMHO, by the time I retire the pilot retirement age will be at least 66, but along the way there will be numerous fudges and stalling tactics from employers attempting to avoid paying pilots to do nothing or little or paying them off.
WRT early retirement, I'd be only to happy to go next year at 55, unfortunately successive governments have robbed us of pension entitlement and tax efficiency's to make that possible.