Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

Hi everyone,
I've got a little problem ( hopefully its little!) with my V reg 1.2 16v 98k. It's all about the oil pressure light.
Had the car serviced about 3 months ago, when the oil was changed and at the same time had the oil pressure switch changed. Everything was OK until about a week ago, when the oil pressure light kept appearing. Now this only comes on when the engine is warmed up ( showing 93+ on temp gauge) and only when engine is below 1000 revs - she idles at around 820 revs.
Since the oil change I've done about 1300 miles. I have topped up the oil with 1litre of oil last week to bring it back to maximum on dipstick and checked that there are no leaks anywhere. I don't think this is excessive for a corsa with this mileage.
Anyone any ideas of how to cure the oil light appearing - apart from disconnecting the switch?

try another oil pressure sensor. i flushed mine and changed the oil the other week. since then i'm now on my 3rd one lol seems to be ok now thou.

Thanks for that. I bought a new sensor, fitted it but it makes no difference. Checked oil level and this was showing just below the full mark.
The engine isn't overheating,as the gauge goes to about 93+ on temp guage then drops to just above 90 when the stat opens. Methinks it could be a wiring fault?