I did 1400 miles last weekend in my 4/4 with absolutely no problems at all. Longest stretch was about 400 miles in the pissing rain including a couple of hours in stop-start traffic on the Rotterdam ring road. The car never missed a beat and I was fine when we reached the hotel.

I would say that 1300km/800 miles is a bit ambitious if there's only one of you doing the driving, but if you take turns and doze when you're not behind the wheel you should be able to do it in a long day. Otherwise split your journey with an overnight stop for maximum enjoyment

Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE