After some more testing I have come to the conclusion that the turbo has failed, I now have white smoke, and if I persist in revving the van it will go beyond 3500rpm and a grating noise can be heard from the turbo.

I have had a chat to my factor and they say that the oil pump, sump pick up pipe and turbo feed pipe need to be stripped and made surgically clean.

Does anyone have any experience in the removal of the oil pump on these?
Are they akin to the VAG ones, sat in the sump?

Does anyone have any good hints or tips when doing these?

Thanks in advance

Liam Hall.