Thanks Richard.
Due to time & putting my back out at work I've had to drop it in the garage for them to have a look over. So far they reckon some gasket to do with the oil cooler (£5 + £150 labour + VAT) and they have no idea where the coolant is leaking from, but want 4 hours labour (£200+) just to "locate it".
As for oil, filter + coolant change - the did not change any if it. The filter is still the same one (I dated it when it was done) and the oil was still black, not fresh when I got it back from them. The water may have been part mine + a top up as I always run mine with winter levels of antifreeze, and it was way under when got it back, but a similar albeit paler colour.
My '98 Disco went in for a head gasket - it had no leaks whatsoever before that - it came out leaking coolant and oil all over the place. Even the MoT tester who pointed out the head gasket blowing has said it looks like a different vehicle underneath - one that was in well kept condition - to one that looks 13+ years old and has never seen a garage.