Thanks for the replies.
The reason for the question was that I have bought some poly bushes to replace the standard ARB ones and the holes for the ARB to pass through are both about 2mm too big!
Eurospares do quote different part numbers but I wasn't sure if that meant that they were particularly different.
Oh, I bought the new bushes from Jeff @ FD!!
So three options I guess, sell the new biushes to a GS owner or buy a GS ARB and fit to my car or buy the correct size poly bushes.
Suppose there is a fourth, leave it alone.
-David-