Hey Neil - welcome to the site.
As myfeckin' pointed out unless you're REALLY attached to the idea of having a nutter colt
it might be handier picking up a whole gpx
Rory (SteelRoe) is local the man for parts - but you should also check out Camskill, RiceRocket and HMSbikes..
Use the search function and you'll find their details...alse the services section on the main page has valuable contact info..
Personally I'd looove to see a Colt with a proper sized Mivec lump in it like a super cyborg
- would be alot of fun to drive if the setup is done right.