Let me just clarify:

There is no black smoke, no whooshing, no loss of power, no warning lights. The noise is not just associated with applying power, it was originally more noticeable on the over-run.

sid wrote:

re turbo noise,my wife mentioned a slight whooshing noise I could not hear it,but she knows what shes talking about,of course,pluged in my diagnostics,no warning lights by the way,came up with turbo boost pressure ,cleared codes,she still insisted ive not cured it,so I took it for a hard drive and at about 2500 it died then picked up instantly.took small turbo hose at top of engine off, found a small hole,taped it up,ordered a new one,job done.

That's exactly what happened to mine, except the small hole was a 3" split & the slight whoosh was more like a tornado! The fact I had to drive 360 kms with it didn't help & I expect that was why the engine management light came on  (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)

Steering column grommet (as suggested earlier)? Wrap an old towel round base of column and see if it makes any difference. Ex AA Series III LWB Safari - Gone
300TDi Disco (bought new - terrible car) sent back after 18 months
Freelander 1 Estate - leased, given back at end of lease
200TDi Disco (bought from a mate with 100,000 on the clock) - Gone
Disco 2 TD5 - sold and exported to France
FR2 TD4 GS - Gone
FR2 SD4 HSE - Now changed for a DS
New model ex-demo Evoque S 180 in white
Unable to order a new DS, so gave up. Now have a Volvo S90 Recharge.

Chalky9
Is the noise still there if you turn the Air Con off?
I have a similar noise but it goes it goes immediately the AC is switched off. Tattoos - Why would you choose to look like the wall of a public toilet?

I had the front turbo pipe split a couple of months ago and noise from that was like extra loud diesel rattle and tappets. Like every noise that the metal bits in the cylinder head make was magnified. Of course it only got loud when the boost got to a certain level. On tickover and light load you wouldn't know anything was wrong. MY13 Santorini Black SD4 HSE