I thought I would add bits and pieces as I find them to this post so if anyone else is considering racing one in any type of historic championship, etc it may make things a bit easier. I found two makers or rearsets - Attack Racing and Raask. The Attack ones have been discontinued but you may be lucky enough to find a set. As for Raask, I don't know much about them but they will cost me AUD$450 which isn't too bad.