Hi Aidan,
Thanks for your reply. Vacuum remains constant at around 20hg before the control valve and is stable as limp mode is triggered. I tend to agree that it was most likely masked by gentle driving initially as I can only get it to occur under high load at relatively low rpm. The customer did mention that it had gone into limp mode prior to the initial damage but had never had the faults read so it is possible the fault existed prior to this. I have checked that all the vac pipes are routed correctly and I'm confident they are.