[Darren69]

Right! Quick update on this issue. I had all the wiring off that side and checked everything and sorted the oil light issue when it was staying on when disconnected fairly quickly but what then took me a lot longer was getting it to come back on when connected. Turns out that cheap Vauxhall replacement doesn't work, it's not grounding through the switch somehow. Glad I kept the old original one as that works perfectly. I need to replace the batteries in my multimeter now, but they worked just long enough for me to find this issue.

So, if anyone has a Vauxhall Aquila and wants an oil pressure switch I've got one you can have that might work! Not even sure what an Aquila looks like so it's doubtful if anyone even has one.

Right I'm off for a few beers!