Drove back from France via Dover last night. No problems with the 90 all the way to the chippy for some food. But for the 1/2 mile or so from the chippy to my house, the oil pressure light came on- never done it before. Checked the oil this morning and it was fine, started it up and the light went out straight away.

Anything to be concerned about? My thinking is that the oil temperatures must have been fairly high which thinned the oil enough for the pressure to drop and the light to come on. Is it worth trying something a bit thicker at the next oil change?

Could just be a tired oil pressure switch?
Quite cheap to replace but get a quality branded one .

Could be a possibility. If I do swap it over, might be an excuse to fit a pressure gauge while I'm at it, in place of the rather pointless voltmeter that's there currently.

Could be switch but they don't come on till pressure is quite low. The only way to tell is pop a proper pressure gauge on it, about £25 off ebay. Mine did the same, changed the switch and it didn't come on but pressure was quite low and on further investigation, the mains were quite worn so i'd personally take it as a warning and at the least drop a gauge on to know for sure and give you peace of mind.

Totally agree with the above comments - but I would suggest an old school mechanical/capillary gauge - £30.00 or so, Durite are good - or...........................
possibly your oil light is telling you that you eat to many chips!