Hi While I'm not 100% sure, I beleive if you can get the correct size diameter traction tyre, then those produced for Hornby locos should fit? I would take the wheel or loco to a Hornby dealer or other good model railway shop and see what they have. Good luck anyway.
I have a Airfix Royal scot and when i needed some tyres for it i got some tyres off a Horby Deans goods loco so as Flashbang as already said try hornby first. by the way the motor from the Deans Good also fitted the Royal Scot. Mick745.