Spent an hour on the car this afternoon, electrics are all sound now, no overheating wires or incorrectly wired cables!
Water temp sensor connected up, TPS calibrated turns and springs into life and as yet no nasty clunks! So I'm guessing my gremlins were being caused by dodgy wiring on the car loom.
I do have a slight grinding sound on crank though, the second that it ran for it didn't happen so I'm fairly certain it's coming from the starter or starter cog grinding on the flywheel, I don't have the dust guard fitted so maybe it's over throwing? I'll move it back with a washer or two when I get a chance.
I feel like it's mechanically sound now so I'm thinking of whacking it on a trailer and getting it to a dyno, I'll do a post in the loan section but guess I can double up here, anyone have a trailer in the Surrey/London area that they would be prepared to lend me?