Oil Pressure Light when Hot

Hi all,

I have a MK3 2004 1.8 which has developed an issue. Everything seems ok but after I've run the engine and it's heated up to running temp the oil pressure light comes on. I've checked the oil and it's fine and sometimes it seems to not come on. Other times it comes on after a good 10-15 mins running at temp other times it comes on almost the second I reach running temp.

Anyone have any ideas what might be causing this? I've checked previous posts which list the switch being faulty or the pump failing but that all relate to the start of a journey, not after the engines heated up. Could it still be a faulty fan or oil pump or is there something else that might be indicated by it only happening when the engine is hot?

Thanks in advance

G