Hi Gazza, are we talking about Benhams in Stockport here ?
I've found that the only members of staff there who have any useful knowledge of the older BMW's are Dave Woodhead and Ian in the parts department. The rest have no clue if the computer doesn't tell them exactly what you want to know.
Muppets
Williams in Manchester is even worse though, actually had an argument with one of the parts guys about the T-piece washer valves fitted to my E30 with intensive wash. He was adamant that not only did no E30 ever have intensive wash but they never had the T shape valves either and was rude enough to actually walk away and call me a liar

Dickhead.
I've never used Williams since and would rather travel to Blue Bell in south Manchester.
Better to go to someone like BMTEC who are knowledgeable about E30's.
Cheers,
Iain T