I didn't sleep well, so I spent the morning catching up on TV - luckily it's too windy for me to have flown anyway. Research suggests that there are 2 different oil pressure senders - one imperial (expensive) and one metric (very expensive), but that the threads are similar enough that either can be mounted until you tighten it up - the wrong one will either not tighten up properly, or will tear the thread out of the oil pump. When Vic got back from running around, we went to the airport so I could see which one is on my engine. There was a puddle of oil under the rear of the plane, where the oil hose from the tank to the heat exchanger was leaking because the banjo bolt was finger tight. Luckily Ken was around, so I showed him, and we agreed the best thing to do was tighten it up, burp the engine and start it to see if that was the entire problem. I was - I immediately got ~60psi. Interestingly, it's also put the oil level in the tank back to normal, so the oil had drained out of the system into the tank by the time I had thought to check the level. Oh well. Now I need to clean everything up, and bring a (I think) 24mm socket and find the torque specification and tighten it up correctly, then I'll mark it with paint to see if it loosens up (I can then easily check all the banjos in a pre-flight).
In the evening, we watched "Solo". It's not a bad movie by itself, but I'm not sure it needed to be part of Star Wars.