She lives again!
Picked up the ignition switch this morning, and came straight back to crack on with it. After removing seat, and column shroud, the wiring around the column was a little wet!? Dried it all off with a hair dryer, the set about changing the switch as I was now convinced this was the problem. Took f**king ages to get the old one out, fiddley as f**k! Got ther in the end though, and fitted the new one. Went to start, and still nothing.
dropped the fuse panel, and all seemed well. No damp, connections seemed sound, but batteries died on the multimeter so couldn't test voltages.
decided to disconnect the immobiliser, to rule that out anyway, but connections were all properly soldered and spliced in, and it was only 4 years old. Soldered and heatshrinked wires back together, and she spluttered to life, then died again. A bit of head scratching and I noticed I'd forgotten to put the fuel pump relay back in after swapping again after the new ignition went in. Put back in and she runs perfectly.
immobiliser module was behind the centre console, so I can only assume it got wet when I removed the heater matrix. All sorted now, and I can f**k off the 306 again!
thanks to Liam, DH, and Andy for suggestions, very much appreciated.
