Griffiths parts help

[onny]

Hi, I have a 1994 Pre-serpentine Griff 500. Can anyone tell me which part number or if the parts are TVR specific for the following:

Pre-serpentine Drive Belt (currently using Halford part number 1125 but its slipping only after a few hundred miles usage).

Petrol Cap.

Road Speed Sensor.

Thanks in advance.