Well,after removing and cleaning my turbo,(you may remember my friendly vag technician wanted 660 quid to do same),I still have the same problem Turbo blades are really clean and the vanes are nice and free,egr valve nice and clean,new n75 valve,all vac pipes renewed.Took it out,pulled well up through the gears,slacken off in 6th and POP gone again.Turn off and on again,it's back.Disconnect maf,no boost at all,reconnect,it's back,so maf is working.Disconnect vac pipe on actuating valve,no difference,still pulls hard up to 6th,reconnect,no difference,and I cannot feel any vacuum from the pipe to n75,so that valve is not operating,either by virtue of the fact that there is no vac from new n75 or the actuator is knackered.Incidentally,I have checked the vac reservoir for leaks and it's o.k.So,something for you top boys to get your teeth into,all suggestions will be tried,and I will post the winners name LOUD