Odd noise during acceleration

Team ... I've got a strange phenomena with my Freelander 2 HSE TD4 Automatic so would appreciate any help from Landy boffins.
When I accelerate from a standing start ( or indeed from a very low speed ) I get a funny sound from 1600 - 1800 rpm. Bear with me on this sound thing -cos if you can imagine a tyre spinning on tarmac for a second or two- thats what I hear. A sort of high pitched 'scrape'. It doesnt happen when the engine revs up in neutral. I've had my local 4x4 garage ( not a LandRover dealer ) have a look at it but they say its normal and is caused by the turbo vent valve opening at that speed. This I guess is plausible but just doesnt sound right to me. Whatever the problem is, it doesnt seem to affect the car's performance but its annoying me now. Any ideas ? or has anyone else got the same effect ? I havent been able to talk to any other Freelander owners to see if they have the same problem
Best regards

yes they are bang on, it is the turbo wastegate opening, my old 2007 td4 was always doing it, especially off roundabouts.........

very many thanks for the info - its put my mind at rest. I still think I'll sell it though !

I have the the same problem is it expensive to cure ???what needs to be done