Sorted.+++

Fuse had blown as predicted. Main fuse panel, carrier 5 (brown, well orange really), Fuse 1, 10A.

Looking at the wiring of the 3 lights in the boot, the 2 in the roof have only one insulated connector, presumably on the basis that the other is earthed to the chassis anyway. But the sill one has both insulated, don't know why. :Confused:
That was the one I was playing with and I was using a screwdriver to lever things out, so I probably shorted it out. I'll be more careful next time. :o

Funny things was, some of the LED's worked dimly for a short while then faded. I can only assume there was some residual charge in capacitors in the controller - enough for LED's but probably not filament bulbs. :Confused:

And I've figured out how. :(
One of the LED festoon bulbs I was using was an unusual design; instead of the usual plastic tube with metal caps it had a solid metal body like this:
http://www.xenons4u.co.uk/58-117-lar...stoon-bulb.jpg
The contacts are very tight and you have to spring them apart quite a way to fit it, so very easy to short on the body. :mad:
On the plus side they are VERY bright. :love:

Glad its sorted +++