.....yes, free wheel hubs (I think) there is a spin lock on the centre of the hub that says "lock" and "Free". It is permentantly pointing to "Lock" but will move (both wheels) to "Free". The left side where the trouble is can be a little stiff but it does move.
Yes there is a 2nd lever (apart from the gear shift) that engages four wheel high, low, N, and 2 wheel high (no two wheel low).
When in 2 wheel high on tarmac the jeep still pulls a little to the left however when in four wheel high or low it pulls hard to the left and when at a stop the left wheel/hub/brake is very very hot and a little smelly.
I have not checked the brakes to see if sticking on one side, I will do this at the weekend. If it is the brake how do I free it or is this a job for someone with a few more brain cells than me ?