I've just got mine off E-bay. They were £39.99 plus £10.00 postage (from Mr Rabbity).
I E-mailed Kniterider who used to be on this forum quite a bit as I knew he had put some on his Mk4. Basically he said that he took the feed from the original Fog lamp wiring, left the wiring loom (which is also directly connected to the battery) in the space in front of the battery with the switch in the on position. So each time he puts his original fogs on the bottom ones come on too.
I've not decided yet if i'm going to do the same, mainly because I quite like being able to put on my original fogs without getting flashed by oncoming traffic or pulled over by the police. I think I might get a qualified auto electrician to set them up separately.