Maybe my question was a bit to specific.
Is it Austin-related?
Sorry but you've been beaten to it!
Barrett is indeed right - it's a Land-Rover and I'm giving him the point for that answer because there isn't much more that can be said about it.
It was a factory prototype mini-bus based on the forward-control Land-Rover made in the '60s mainly for the military but also for various utilities such as fire brigades. Many found their way into private hands after serving out their time.
Seems it remained a one-off.