To be fair, I think this site covers pretty much the Chipmunk World, there are people here from as far way from the UK as the USA, Canada and Australia. There are even a few European contributors!

You can usually get answers to specific questions. There are detailed diffrences between the Canadian built Chipmunks and the British and Portuguese built machines, but I think these are small enough for the same information to be used if applied intelligently. de Havilland Support in Duxford can provide the current technical news sheets, for the British built Chipmunk, on a subscription basis. see
www.dhsupport.com . For parts it depends on what parts you are looking for. I've had help, with parts, from as far away as its possible to get and still stay on the planet. As far as clubs go, this site is far more useful than any Chipmunk club I am aware of.
regards
Nigel