Fixed this. I had another look at the throttle body and reset it again still no better but it reminded me of the egr reset in block 74, had a look in there and noticed that the min value was 0.7volts and the actual was 0.9volts ran the reset and min now matches actual at 0.9v , back to fuel trim and it is now spot on, the map sensor is still at 280-290 mbar. a test drive and a long time at idle and the fault defiantly gone. The ecu must have thought the egr was open a bit which would affect the map and so compensates.