I noticed a slight drone coming from rear end of vehicle in the last couple of weeks. Over 30mph increases and lessens when slowing down, thought about cat and possible wheel bearings but having raised wheels noticed an unhealthy noise coming from dif. Can anyone advise about best course of action if it is that, split and repair current one, complete replacement or is there any chance that it could be something else that is not so disastrous.
I would appreciate any advice from anyone who has any experience of this.
Thanks in advance.

Have just had a new diff fitted to my 2010 MY at 58000 miles. This followed a complete rebuild of the original diff to (unsuccessfully) cure a loud whining noise. Fortunately, all of this work was carried out under a LR extended warranty.