South Easterly Day break yesterday morning

I had a brainwave to do with Teals starter issue and realised that the problem with the starter could be related to the heater plug being wired to the ignition switch and sure enough once I disconnected it she started perfectly. I thought the key switch would have disconnected the heater plug as I turned it to start position but apparently not. Either way it was a quick fix. There was also never a charge problem as it turned out it was the oil light which was on. So either I have no oil pressure AT ALL or a dodgy sender. So either I need a new sender or a new engine. Next job is to check the oil pressure with a gauge. I would be surprised if it is a complete pressure loss as I can't think of anything that would cause that to happen that suddenly and it still sounds fine.