Right, why turbochargers on diesels repeatedly fail ...

Most people switch off the engine as soon as they come to a stop. As such, the hot turbo bearings then carbonise the oil around them. So you've now got little chunks of what is basically charcoal in and around the pipework and turbo bearings. Over time, it builds up, and, as in humans, these clogged 'arteries' lead to a heart attack or heart failure. In this case, the turbo seizes up.

So if you replace the turbo, you MUST replace all the feed and return pipes. Else the replacement turbo will not be getting the oil feed it needs, and will seize up again.

Now, if the 'mechanic' is just going to randomly replace the turbo, and doesn't know if it will fail again (or why it might fail again), or even if the turbo is actually the cause of the problem, then I suggest you need a different mechanic.

It could also be the EGR valve, but yes, more likely to be the turbo.

Cheers thanks a lot. It quick hard to find a decent mechanic around the west mids.

If so, a sad indictment of the state of the educational system for non-academic youngsters in the cradle (now apparently graveyard/museum) of the English automotive industry.