You were right about the oil cooler Gerrit, the engine held it's pressure much longer and didn't drop anywhere near as mutch as it usually does.
The good news is,the engine was as sweet as a nut and pulled like a train, the bad news is I only got the two practice sessions completed .
In the first race, did warm up lap and first lap of the race (heavy rain), then it was red flagged because of an accident, at the restart on the line I noticed smoke coming from under the tank, the matrix on the cooler had split and was dripping oil on to the exhaust headers, so had to pull out.
We checked the oil and it had lost half a litre during those two laps, so maybe the red flag did me a favour.
So now it is one round each for and against oil coolers

all in all we still had a good weekend (even though the weather was crap) and came home with an engine still intact

Col had a good result with a 2nd and a third.