Water leak is now fixed!
Had 4 leaks in the end, Water was leaking from the main wiring harness, there was a gap in the sealer in the passenger footwell, Leak from the windscreen and a leak from the pollen filter housing. Car is bone dry and more or less back together.
Got a few things left to do such as reconnect the speedometer cable onto the gearbox end, refit the seats, refit the steering column shrouds but it's getting there!