Abs light on the bloke im buying it from says the car has been stood a couple of months and it wasnt on before it got parked up could it be that its got dirt on the sensor. ste

Tell him to clean the sensor to put the light out. It is bound to be more than dirt. Once the ABS light is on, you usually have to empty your wallet to put it out. Maybe it's a sensor, but not from dirt. Maybe a wire broke, sometimes a tone ring splits. You can easily do a visual inspection of the sensors, tone rings, and wires; but if those are good, it's probably the control unit. I have pasted a picture of the tone ring on the axle. The rear tone rings are inside the drum and less susceptible to damage. Make sure the tone ring is square on the axle and not loose--no missing teeth, etc. Sensor should be square on the tone ring. Let me know if you have more questions.