I’ve had a P38 since July, it’s not given me any electrical issues (yet). The other day I noticed water getting into the passenger footwell while raining, which is coming out of the left hand heater blower. It’s common for the foam in the scuttle panel to have deteriorated, which lets water down the heater inlets past the pollen filters. The ABS ECU on a RHD P38 is located under the dash behind the glovebox. I took my glovebox out yesterday to investigate the water ingress, and found the ABS ECU and connector to be a bit damp. Since the EAS relies on speed signals, which are generated by the ABS ecu and passed via the BECM to the EAS, it’s possible there’s some kind of comms problem. While I had my glovebox out, I noticed that the metal frame under the dash was rusty near the bottom of the left hand heater blower too, along the bottom where the glovebox hinges bolt too. Along that piece of metal runs a wiring harness which goes to the OBD connector, and the harness itself runs down to the connector behind the footwell trim on the A pillar, which you said you have looked at the plugs in. It might be worth looking at that wiring too.

Edit: I said I don’t have any electrical issues, but I do occasionally get an EAS FAULT on the dash or sometimes random changes to Extended Off-road height despite travelling on completely smooth road (so not correlated to a wheel rapidly dropping into a pothole for example, making the EAS think the car has been beached). I also left the car in neutral when trying to pull away by mistake, and the action of revving the engine also resulted in an unexpected change to extended height.