FIXED i reread codes and it came up with misfire on cyl 123 no mention of cam sensors changed coil and plugs still the same found a audi forum which mentioned a ecu reflash to reset cam sensors which some times is required after cam belt replacement which i did fit new cam belt 40,000 miles ago it said to disconnect battery and join pos and neg leads together and it seems to have worked i did check cam belt condition just in case it was flapping about but all ok