reply from one of our Lincolnshire regulars:-
An excellent place is 'R.C.E. Duckering' based at Toft Newton (near West Rasen) Tel: 01673 866659 or 07889 580890.
Although I have not used his services - we exchanged our Mk2 (needed a paint job) for a Mk2.5 instead - I was shown round his workshop and was mightily impressed with the standard of his work.
Hope this helps.