You could also try Derek at DS Motorsport in ELY (Cambridge) he builds
and restores RS200's and a centain gent in Markyate is a customer
of his.
The box he built for me has bigger bearings in it than the other fellows
and is the only one I've not managed to destroy (fingers crossed)
yet.
He charged me £900 with the ATB etc.
Give him a call 01353 720586