After over a year of trying to solve my 'low oil pressure' problem I have finally found the cause... The car has had a new oil pressure switch, a new oil pump, the sump off about 3 times for inspection and the oil pickup checked and cleaned each time, and still I continued to get the red oil can and 3 beeps. The car only used to do it once warm and originally after a blast but was getting more frequent. I was really close to chopping her in which was the last thing I wanted to do as I'd get peanuts for her, along with the fact I still love driving her ! After lots of reading up on various forums I came across a thread with a bloke who had a similar problem and found a cure, if only I'd of found it earlier, would of saved me a few £100's... Turned out to be the PRV pressure relief valve (hockey puck) which is part of the PVC system and comes out of the side of the rocker cover. It was basically an oil breather issue, car is now running sweet again ! Hope this thread helps anyone with the same problems, might save a packet !