This might be a complete dead end idea but, the LAA do a CD covering the conversion of VW engines in their heritage plans section. I'm guessing this might give the engineering detail needed for the work.
If it does, I'd suggest speaking to Maurice at Eyetech Engineering http://eyetechengineering.co.uk/
he'd be more than capable, and I doubt anyone would question his work. He helped us out more than once with daft little problems
The quickest way to fall out with people is, discuss politics.