Andy
Did the pressure drop once the oil warmed up (assuming it did warm up) Cold oil will always generate a higher pressure reading as it is more viscous?
Gone are the days when the gauge actually measured the oil pressure from a hydraulic line, now the majority are taking data from an electrical sensor somewhere in the engine.
As a result 9 times out of 10 an electrical issue is down to poor connections or poor earths (or both!) So I would recommend finding the sensor and cleaning the electrical connector to it, also have a good look at the earth for the dashboard wiring and instruments.
