Hi this might be too late but i have just contacted him on the airgunforum site under nickg, But i have noted that the tuner called tin bum is now doing a kil for the lgu/lgv rifles if you are still having problems. All the best Graham.
p.s have you opened the transfer port up from 2.6mm.
Got my tuned .22 LGU back from NICK GIBNEY a few days ago after he had worked his magic. It was the first .22 he had done but had done many .177's. The .177 and .22 both use the same actions and its only the barrel bore size which changes which I discovered after I had bought a full set of spare action parts to enable me to return it to standard if necessary. Its now a different experience altogether to shoot with virtually no recoil at all and a lot quieter too. Just as powerful (11.40) but that is dependant on the pellet type some samples of which he sent after he had tested its performance after his 'tuning'. Cost? A well worth it £180.00!