Check the oil pressure sensor plug and wire for connection. I use BWD Intermotor sensors that I get from Advance Auto using the TRT30 online discount code for 30% off and specify in store pickup. Here's a picture from when I changed the sensor. The sensor on the left. As you know from working on British cars, if you decide to run an oil pressure test, be sure to check for BSPT sensor threads. I use small amount of teflon tape on sensor threads when I do a replacement.
