Taylor and sons - Ben Taylor of Theoben fame.
He is even rebarrelling TX200's in .20
Apparently he has a range of 15.6 grain .20 lead pellets that are the bees knees.
I must be honest and say that I cannot see the point myself of a nearly 16 grain .20 when the same mass in .22 will travel nearly as flat yet hit harder.
However I am sure that his shop and service are both first class.