Found a pair of stainless matched bolts hiding in my "odd bits" box. That was lucky. Thanks all for the other info.
"Is it possible to shorten the throw of the gear selector. I have moved the rod but it seems to keep the same throw but just move the entire thing up or down. I can’t get it to expose more than one of the supposed 4 adjustment points on the rod though even with the screw out." You can alter the throw if you move one of the levers round a spline on its shaft, then you have a new range of adjustment. Mark the position of the lever on its shaft before changing anything in case you decide you want to revert to where you are now
Wearing different boots makes a difference. Boots with thin soles and uppers will effectively increase the throw and thick soles and/or uppers will effectively reduce it.
