HELP astra j 1.7 cutting out

[Lsmcdti]

I have an astra j 60 plate 1.7 cdti a few weeks ago it cut out and when i started it back up it would judder and cut out again, anyway aa bloke only found an egr code, it started and drove fine again so went home, i removed the egr which was not that dirty, cleaned and replaced and has been fine for approx 800 miles but on the way to work today it happened again, massive loss of power then cut off when i started it back up it cut out again, then started again and idled slighly rough but when i Pressed the accelerator nothing happened, i could put my foot to the floor and had no revs at all, it cut out again then on restarting it drove as normal again, got to work and waited for the aa , he got egr code again, he operated the egr via his diognostics and it was working fine, he said he thinks it might be getting stuck open but how can i be sure its the egr at fault before i pay out on parts or repairs ? Any ideas, if the egr was stuck open would it sit idling but have no responce from throttle, Any responce would be much appreciated, thanks