My pedals have a 13mm bar going through to pivot on which used to be threaded into the housing (which i am not using on the locost). Would it be ok to cut the thread off and put a pin on either side to hold it in place?

Shold be OK. Lots of tin-tops are only held in with a circlip so a roll pin would be just as secure. You'll want to lock the shaft to stop it rotating in the bracket (and wearing the holes) instead of the pedals rotating on the shaft. Ford use a flat on one end of the shaft and a D shaped hole in one side of the bracket.

adrian

Cool, thanks