Having asked here a few weeks ago about sorting a rear passenger door being permanently locked - and getting no replies :-( maybe it's a rare problem. So in case anyone else encounters the same thing, I can report that it ended up with the local garage. It was reportedly a real bu**er to remove trim with door closed. The motorised lock unit had failed, and so its casing had to be broken apart in-situ before door could be opened. Problem now sorted - 2 hours labour + £39 for new motor/lock + vat. A pretty fair price IMHO - but frustrating cos I never sit in the back (...those were the days...!)