Thought I better clear this one up, the problem all along turned out to be maf scaling, disconnecting the avcs just masked the fuelling issues and made it look like an avcs problem, I presume my car was either mapped for an intake at some point and then put back to standard before I bought it, or because it was fist mapped at 69k (roughly) the maf may have been well past its best, and as I had fitted a brand new maf it had thrown it all out, I'm not going to get into any more mud slinging, suffice to say, my car now has a good make inner wing cold air intake fitted, holds boost correctly, runs like a champ, fuel trims are now where they should be, does not pull timing and has not gone into limp mode since this was fitted, probably a couple of months ago now, so my problem was down to a poor map