Hello Martyn. From the manual the belts are 1.5 x 83 x10 for the lathe and 1.5 x 70 x 10 for the milling head. The only place that I found them was Banggood. The originals were steel belts but I got rubber ones, much cheaper.
The milling head belt was far too tight on mine, I got round this by making a new pully with one tooth less.
Let me know if you want further information on this machine.
Steve