To give some update on this I managed to remove the suspect part.
After a few emails backwards and forwards to Vitesse it is starting to look as though the problem may not be in the remote gear lever extension even though it is one of the earlier versions (2011) without welding. It is not yet definite but the problem may be in the selector mechanism of the gearbox itself. If this is the case it is an engine and gearbox out job. I will know for sure in the next day or so.
Vitesse tell me that if this is the case it is extremely unfortunate as it would be the only case of gearbox failure in over 6,000 gearboxes that they have supplied.
I have to say that Vitesse have been fantastic in all this with prompt and helpful replies to my emails. I wish all businesses were as correct and helpful. Judging by this I can only say that anyone considering a gearbox conversion for an MG or one of their other products, including the Morgan Plus 4 automatic conversion, should have no concerns about aftersales support.
https://www.vitesse-ltd.com/blogs/news/110594119-automatic-for-the-people-morgan-plus-4-automatic
