when you say knackered are you referring to a leaking pipe, whats the possibility of it blocking up as the place i purchased the turbo from recommended to change the pipe as they can become blocked up, do they have a large inner diameter
Would be more than a little worried about the state of the rest of your engine if an oil supply pipe had blocked.
If you want to check it, take out the fuel pump fuse and crank the engine over to allow some oil pressure to build up. If you keep the oil feed disconnected while doing this, you will be able to see how much oil is coming through. It can take a little while though and will be a little messy.
Alternatively, undo the oil return pipe from the turbo like most people do, then crank it over until oil comes though.
Why change it if it's OK and it doesn't leak? The two copper washers have to be changed, obviously! Clean everything thoroughly.
The coolant in/out hoses should be changed, IMO, even if they didn't (yet) leak
Before firing the engine you'll have to prime the turbo, so you'll see then if the oil feed hose plays tricks
my vauxhall dealership dont even know who mig vauxhalls are.
The turbo company recommend the pipe to be changed as even if you can blow through it the pipe still has gunge and carbon build up which can cause blockage or even decrease the amount of oil going through it