i took it up to rank rotary last night and let them check over it.
they tend to think the intercooler pipe is the problem, they seem pretty certain about it.
they checked the wastegate arm and that was fine aswell.
they said if the turbine housing or manifold had cracked it would sound like an exhaust leak.
i might give daz a buzz today about it, rank's quote for cooler piping was, umm... a wee bit pricey for me! 
Mat
