I've driven around with the whole of the back clear (suspension, axle, etc exposed) with a friend trying to identify the problem but no luck. Was going off to a Morgan garage this morning but they couldn't sort it last time so will probably just go to a local garage and have it up on the ramp. One fear is that it might be a cracked chassis (at 147000 miles) but I gather this is unlikely with a galvanized chassis. Thanks Graham anyway...
