Gents as stated above on a 2007 4.2 I am getting a light whine at 80mph whilst under load it disappears at 70 and over 85
Gear change doesn't change it so it is purely speed related so thinking drive shaft or diff any ideas anyone

Is the wife in the car?

Not when it is a light whine but certainly when it is loud through the range

Unnecessary quote removed

Sandyt did you get to the bottom of this?

Nope it is still the same and another 8000 miles in so who knows?No faults found and drives absolutely perfect

My 2011 did the very same thing. Turns out there was a service document pertaining to the transfercase chain micro wear on certain l322 / D4's and within a certain vin range 2010-2011 production being a factory / production tolerance fault issue.

The whine was not loud, only vaguely audible under load between 100-120kph.

JLR replaced the chain under maintenance plan approx 10K km ago, been perfectly quiet ever since...

I dont know of my transfercase is the same as yours, i know they were changed to different models during the L322 production.

Who knows, just maybe its the same issue materialsing in yours..

Interesting thanks for the info will have a look thinking of putting on a four post ramp and running up to see if I can hear anything

Just swap to a Barolo and slow down a little so you don't spill any. You'll be fine. 2017 5.0 Autobiography Supercharged
2005 Merc SL350
2005 Disco HSE 2.7 oil burner

If it goes when you lift off - it could be the rear diff. An oil change of the rear diff should be done every 80K 

Service bulletin LTB00498NAS1 regarding the transfercase whine attached, yes its for later models, but still maybe worth a look...

Click image to enlarge

Mine was the same although around 70-75 was peak whine. I changed the transfer box oil for new factory oil and it got no worse over nearly 40k miles. Taking a rest from Land Rovers for a bit.......