we'll be taking in all sorts of terrain
Beware! Make sure you've got good excess insurance!
Just because you're renting a 4x4, they won't let you off! I rented a brand new Disco once and used it fairly heavily offroad - the spare wheel (up under the rear) being a solid block of mud was the give away; they shafted us.
I had a Quashkai (or however the feck you spell it...) in Scotland last month, not off road. Hertz excess was £2K!
On the other hand, I noted that depot had a Ftype convertible for £220/day - for the same excess. gets my vote next time!