GW its both shock mount on frame and linkage holes threaded, (not me that did it it was a mate with big pudgy farmers hands!!)
just got back from local engineering firm, very nice chaps and the guy is an mtber, cant find nut insert that would suit so is going to helicoil and see how we go. i guess if it screws up (sorry couldn't resist!) then just fill in with weld and re tap.
gutted about the inserts though, local fastener company didnt come up with anything just the rivnut type which wont suit, may dremmel a nyloc down just for belt and braces.