It started and ran no probs to the petrol station, it was just after being on boost in 3rd that this has happened....

Like i said, when the pump is priming, the injectors are "squeeling" like they are opening. And they shouldn`t open until the flap is pulled down by the vacum from the engine/turbo.
Possibly needle inside metering head jammed wide open and flooding the plugs up with petrol??????