[landrovered]

Jack up the rear of the car.

Do a visual check of the CV boots to see if they are torn. If they are not torn...can you feel grease in the boot or do they feel dry? Anything feel out of sorts when you rotate the rear wheels while feeling the CV and the shaft. Anything dripping, leaking or has anything dripped or leaked in the past? Do the CVs feel like the bolts holding them together are tight (they have been known to loosen).
Turn the wheels to see if you feel any roughness in the bearings on each side, also check for play both top and bottom and left and right. Do you hear a dragging sound coming from anything when you turn the rear wheels?
Do a visual inspection of the rear suspension and brakes, is everything in order? Push/pull everything to see if there is any play in any part of the rear suspension. Is anything lodged in the brakes (small pebbles or rocks, sand anything that could make noise when the wheel turns)?
When you drive does the sound increase, decrease or remain the same if you turn left or right? Does it occur in deceleration, acceleration or in the neutral part of the power band? Does it change when you apply the brakes?

Do all of these things and report back.