Rolling Roads in Yorshire

Hi, i have just recently purchased a 1983 GTI that is a running a 3A 2.0 block on Bosch K Jetronic. Not sure if the the head is modified or what other mods have been made, albeit it looks pretty standard. The car is running rough at the moment and wanted to get this sorted on an 'old school' rolling road and see what BHP it was potentially running. Can anybody recommend an engineer and rolling road within Yorkshire that is competent with these engines?