Thanks for your replies boys, Dave H thats awsome pal thanks, printed off ready to explain exactly what was happening to my customer!
Dave E, yes this one was almost exactly the same, stripped back off turbo, found a lots of carbon powder built up around vains, but also the spindles for the vains were tight (not stuck) but tight, I gave it a good clean, worked the spindles with a bit of the magic stuff, slipped it back together & hey presto Robert is my mothers brother. Happy days.
Again, thanks for your input.

Jon