I now have...

...a working fuel gauge. All the bits have been fitted for a while, but I've finally got round to fiddling with the sender in order to make the reading meaningfull (it had been reading past full until the tank was nearly empty).

I'm off to buy the bits for a temperature sender adaptor this morning, and then I can see how hot the engine isn't running. (I suspect the thermostat only opens on long steep hills and hard motorway runs, but this may prove the point).
Its nice having an engine where temp isn't an issue, but seeing as I've a gauge, its worth wiring up for peice of mind. I just hope its better than NOG's gauge, which usually reads in the red for some werd electrical reason. I don't worry too much about that anymore, as one day I pulled over to investigate, and found I could leave my hand on the rad without paint, dispite the gauge nearly being on the stop. I think the root problem is a Britpart(suprise, suprise) voltage regulator, but I'm not totally sure.