If you want to use decent engine builders around doncaster or near the i would use norris motorsport in derbyshire or motorsport developments or very close to doncaster area six motorsport . Ian deals with zetec turbos but he invented the zvh and has done cvh turbos as well so he could help you out and he is a very honest and helpful guy . I tried to get in contact through ebay about power conversions but had no joy and have not seen him advertising on ebay for a while

hope this helps

cheers paul