Agreed. Water temperatures are not as big a concern as oil temperatures on an AAZ, in my experience.
I don't know how heavy your Land Rover is, but the guys who have AAZ engines in VW Vanagons all report pretty high oil temps.
If high oil temps become a concern, plan for a sandwich-plate adapter and air-cooled oil cooler.
Don't waste your time with trying those bigger oil/water heat exchangers, promoted by Diesel Geek & others. I went this route and it had little effect on cooling the oil, but a big effect on my wallet. (It did warm the engine up faster, but that's not why I bought it.)
A bigger turbo than your stock AAZ turbo will drop the oil temps, but mostly because it won't spool as well as your tiny K03. If it's not spooling, then it's not heating the oil. For an off-road crawler, I would think the early spool of the stock AAZ turbo would be a big advantage.
Water temps got to at least 250(limit of my gauge). I have one air/oil
cooler, but have since been given a 2nd one, an intercooler, and a
slightly larger new al radiator for cheap. I am fitting a VNT 15 turbo,
putting in totat seal rings, and had to buy a new head due to the over
heating. Supprisingly I didn't see any signs of leaking a head gasket,
but I had deep cracks, one prechamber that falls out on it's own, and
the rest are somewhat loose. My truck weighs 3500, so quite a bit more
than the rest of you, which is probably why it gets hotter. I actually
had a k14 on it, which still spooled well. Anyway, in trying to cover
all the bases, I know that more water flow cools better, so that's why
I was asking. I did have a new thermostat in, so that wasn't the problem.
Stock cooler is also on as I had to use it to fit the remote filter kit.