Neil,
On my 1994 plus 4 they are as follows, probably similar on yours although no guarantees.
One relay is for the ECU, one for the stepper motor and the third for the fuel pump (I think). I've had the engine die when running and fail to re-start when one broke and have seen one other Mog with the same problem. My spare got him going. I now carry a spare at all times as the vibration causes their internal connections to break (on a regular basis). Bosch part number is on the top, any decent auto electrician can supply for about £6. Don't use a standard five pin relay as the internal wiring is a bit different.
Jim
