Alternator -1995 XJ 4L

Excuse the request for help - if I was at home I would look it up in my manual. Unfortunately, I'm at work all day and it will be dark by the time I get home :(



My 1995 XJ's alternator appears to have quit whilst I was driving it last night. The volt meter was showing 9v and the lights were getting increasingly dim but I just managed to get home before I ran out of power. There was no sign of an ignition/alternator warning light.



I suspect that either

1) the field coil supply has failed

2) the battery has a dead cell

Or

3) my alternator is dead



In the hope that it's 1), can anyone tell me which fuse or relay is responsible for sending the 12v supply to the alternator field coil?



Thanks