Thanks for the prompt reply fellas!
I have had the transmission out twice in the last 8 years. I am not interested in ploughing a further £1500 - £2000 into ANOTHER rebuild. Specialists in the UK are so few and far between that I would have to get it transported to another county to get it fixed. Nobody near to me is prepared to work on it, except a local , so called "Classic American Restorers" who buggered my car up in the first place.
If I cannot make a simple repair myself I will just have to cut my losses and sell the car as a dud. Sad end to ten years of (largely frustrating) ownership.