Thermostatic Radiator Valve (TRV) Spares identifies some of the spares associated with the Manual and Thermostatic Radiator valves.

T1002W0GB Replacement thermostatic head for all. ZS100 Set of 10 range stops for all heads. ZS117 - 1/2 B / E Spare 10mm / 15mm nut and olive sets for VT117. Packs of ten.
T4021GB Replacement thermostatic head for all.
T9002W0 Replacement thermostatic head.
H100 - ZE Manual head with locking ratchet. Pack of 25.
T100MZ actuator with remote sensor and remote set point adjustment. ZS100 Range stops for thermostatic heads. Packed 10 pieces.
ZS100 Range stops for thermostaticheads. Packed 10 pieces.