Upon slowing down and trying to get back up to speed I then noticed the boost gauge was instead going into the vacuum side of the gauge buy about 0-5PSI
When I got home pulled out the EGT probe and the end had snapped off and If I could hazard a guess it's gone through the turbo

Gonna start taking things apart tonight to do a proper diagnosis, but if anyone has any other suggestions as to what might have happened, please fire away!