Its like some sort of restrictor kicking in, the car has a k and N filter which has been on it for ovr a year, and never did this before, the boost solenoid was replaced @ halleys 3000 miles ago and the MAF is also under a year old (had a few mapping issues and fried the chip)
i tool it onto the motorway and gently took it up the rev counter in every gear and it was ok.
once hot it was sluggish again.
car is a 2001 classic wagon with a the usual mods