Looks good from what I can see, the wheel hubs look a bit odd mind - Gimson themselves sell a hub for that motor though that does warp a little easily for my liking.

BeltingOnline is a good shout, might be worth checking GearsandSprockets.co.uk as well, they do belts and such too, got my BW parts for a spinner from there. Motor suggestion... could go with a Turnigy SK3 outrunner (for example - https://hobbyking.com/en_us/turnigy-...ner-motor.html) but a PropDrive is a known element and works, I'd probably stick with that.