Thanks mr240z, will give them a call this week & get a price. Warren also came through for me as his other customer didnt want it, but I'm actually waiting to hear back from a local I met yesterday who may have something in his shed.
Hey huw, i specified early '71 as there is a difference after 8/71, front and rear circuits are switched, pushrod depth changes & front and rear outlets are closer, meaning a change in booster assembly if I want to use a brake MC from a later zed & redoing the brake lines (not enough play & too brittle to muck around with).