Awesome GTI diagnosed my issue as a imminent turbo failure last week while having my car serviced, however due to them being 60 miles away it wasn't feasible to have the turbo done there.
Having it done at a local garage and they decided to strip suspect parts on the car first after hearing the same noise on a 2.0 seat leon tdi to see if it could be anything else. They said in terms of the turbo it looks fine and the ball is in my court.
Due to it only costing around £500 fitted, for peace of mind after hearing some horror stories on here i'm having it done but if the noise does develop in future then i'll look at this solution.As well my car is on 82k, which does sound like a likely age for a turbo to fail on a BKD, whining noise and metal part or not.
2006 110000 miles standard map recon turbo with updated compressor wheel turbo clinic Leeds 520