ok i got my fault code reader through and i just update you on the problem first,, basically i drive it everday and can go ages before it kinda judders or stall whilst driving as if its running out of fuel but i always keep it topped up and it did it few days ago with a full tank
codes are ;;;;;;;
00544----------maximum charge air pressure exceeded
00561----------mixture adjustment control
16487----p0103------mass or volume air flow circuit-high input.may be due to a low
16500----p0116------engine coolant temp circuit-range/performance problem
cheers guys