Decided it was time for new dampers and a general overhaul as there is a 'clonk' when first reversing, and again when going forwards. Got them off surprisingly easily, and have stripped one down. The gasket between the top of the spring and the housing had all but disappeared, and the metal was shiny through rubbing - but no groove to speak of. The top mounting is a ball race in a Metalastic bush, and the bush is fine but the bearing shot. The bearing is caulked into the housing, but came out easily enough. It's about 60mm in diameter and normal enough looking, but has built in metal dust shields on both sides, and the inner race appears to be in two halves.
Assuming bearings are bearings, I went to a local supplier. Obsolete he said, but he managed to locate a couple at 36 quid each plus VAT and delivery (to him).
The damper on that side moved easily by hand in both directions, but the car didn't float when driving. There must be some serious friction in the suspension. ;-)
Rimmers don't list the bearings, but do exchange units - POA. Their damper prices were ok, and I ordered them, gaiters and 'shims' for both sides. Parts will come to about 250 quid including the bearings. Anyone got a Ford for sale?