I've a wet patch under the car towards the rear, just inside the rear driver's side wheel. When I had a quick look earlier the tank fill pipe was wet where there is a rubber coupling but it seems to be coming from a large cylindrical item above it. When I put my finger in the fluid it doesn't smell like diesel, looks and smells a bit more like clean oil. Could it be hydraulic oil of some type? Where's it coming from? 2007 Range Rover Sport TDV6 HSE- Cairns Blue with 22" Stormers

The rear diff breather pipe terminates near the fuel filler (it's clipped to the fill pipe). Might be coming from that perhaps. The only other thing that comes to mind in that area might be the charcoal cannister in the petrol fuel tank but as you have a diesel I assume that's not relevant. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Thanks RRSTDV8, I'll have another look and see if it's the breather. Might try getting a picture too. 2007 Range Rover Sport TDV6 HSE- Cairns Blue with 22" Stormers