I had a Vauxhall Cavalier petrol which did that.......... a brand new car and it had 5 to 7 litres too much oil in it (yes 5 to 7 litres!!). Was fine after I drained off the excess.
Pete
Impressive as always, and I shall follow this thread with interest - even though I don't have a Range Rover!
That's a huge piece of kit there....... just to move a bit of hot & cold around.......
Pete
As long as the plug is well seated, the lack of the fixing studs shouldn't make a difference - they are just there to stop the plug pulling out.
Sorry - I would love to be able to say that that was the problem!
Good luck.
Pete