Sometimes its better the devil you know, the disco has served you well and had all work required done on it. My sister TD6 has had countless work including the electronic handbrake, oil pump, timing belts, both egr's, gearbox oil renewed and loads of other bits. Nice when it works, expensive when not.
I had a shogun and it was horrible, cost me a bit in repairs as well as the fuel filler neck rotted, let water in and wrecked the fuel pump. I would personally stick to an older landrover, parts are cheaper and easier to work on. No idea of value of yours, best have a look through forums or gumtree for an idea of prices.
Cheers,
Iain