THE first thing to check on an ABF is the ECU relay.
You can test it first before you spend the huge amount of 12 quid on one.
Run the car for a while, either drive it or just let in run for 15 mins.
Stop, take out the relay and see if its warm, put it to your cheek is best.
If warm its ok if cold on any side then replace and that will be the source of your problem.