Fairey Overdrive models?

Evening all

I have just signed up as a new member. (Port Elizabeth - South Africa) Great to be part of this community.
I am in the process of restoring a series 2 109 hardtop. Having a great time.

I have been given a Fairey Overdrive - what a gift! It needs a bit of work. Before I commit time and money to its restoration I need to find out whether there were different models available at the time. I have precious little information about where it came from. All that I have been able to determine is that it might have come off an early Range Rover. Is that possible? Would it be compatible with my series? Input welcome.

Cheers
Dave

It's possible the early Range Rover only had 4 forward gears. More likely to be from a Land Rover. As far as I know only one type. You can download the fitting and parts manuals if you google.