From bndabrasives.co.uk:

• Discs:
  • Generic 300mm hook-and-loop sanding discs are suitable:
    • Silverline 934116 Hook and Loop Discs 300 mm, 80 Grit - Pack of 10
    • Silverline 436756 Hook and Loop Discs, 300 mm 120 Grit - Pack of 10
  • Awuko KT62X Aluminium Oxide 60 Grit (Suitable for wood and general metalworking)
• Belts: BND Abrasives Belt Builder: Awuko KT62X 60 Grit - 150mm x 1676mm (10 belts) SKU ABC150167660KT62XAW