No decent pics mate im afraid, but it just involved getting a couple of alloy blocks the right size, cutting them in half and then drilling a 16mm hole through the two halves obv. (with the joint in the middle).
Philloy did them for me.
Also had to fab brackets onto the rear crossmember to mount the blocks. Then the end of the ARB has the standard mounts ground off and a hole drilled instead for the droplink. Droplinks are the same length as standard shackles- i found them on ebay!
Then i just modded the shackle brackets on the wishbones to accept the droplink.
I did it after being in contact with the guy from southampton who recently used to race that white (and later red) S1. He had a very beefy rear ARB on the white car that was custom made but was the same shape as the standard item. All i would have to do to fit a bigger one is have it made to same dimensions as a standard S2 one but thicker, then drill the holes out in the alloy blocks to suit the new diamater bar...