well based on what i was reading online last night, we ordered and fitted a new g450 sensor this morning. despite no real evidence of it being faulty, like fault codes for it and indeed the vas test saying it was fine!
fitted it and went thru the adaptions again, and boom, light went out, cleared engine light FIRST TIME....... and no more limp mode. all in 10 mintues.......
it wouldnt do this at all yesterday. i spent about an hour going round and round with the diagnostics.
anyway my boss is using the car this weekend to make sure its ok. we'll see.
obviously the sensor was faulty enough to upset the ecu stopping it completeing the adaptions, but not enough to flag up a fault specifically for it.
if i were you... for £45 and the 10mins it takes to fit, id get a new g450!
i think vag are guna be seeing alot more dpf faults in future!