With reference to the Mamod wheels, if you search among the drive belts for Hoovers etc. in Homebase and the like, you can find rectangular section drive belts that are a tight press fit on Mamod wheels; two on each back wheel, and one on the front ones. Sorry I can't remember exactly what machine they were for, long time ago, but I found the ones I have by taking a wheel with me and holding it by the packets. Same bands for all the wheels. It is quite hard getting the rear ones on, but that's no bad thing. Fitting these improves the appearance of the standard Mamod steam wagon a great deal. Good luck with your build.