I got the handlebar details at club on Thursday. I was broadly correct, but wrong in the details. My friend knows somebody who owns a CNC company, and he made the risers, which it is thought clamp onto the stanchions. The good news is that my friend never fitted the risers for some reason so he's probably still got them. Also he lives in Redditch. The bad news is that though he is out of hospital, he has been very ill with the C-DIFF bug and is still recovering, so I wouldn't want to bother him at the moment. If you haven't found another solution beforehand, I'll put you in touch with him when he's recovered.