Ok so for this dual variated project the free wheel needs to run in reverse as its on the other side of the bike to a standard single variated setup. Basically what this involves is installing the freewheel with its outer face (shown below) facing inwards. Unfortunately this means that the freewheel needs someway of being locked in place as when the bike is pedalled it automatically wants to unscrew it self from the hub.
So here's what I did. I drilled and tapped a hole in the side of the hub so I could install a thin screw headed bolt (shown below in red).
This meant that when I threaded on the freewheel face down. I could back the bolt out with the use of some pliers so that it would lock into one of the tabs (shown below).
It works the freewheel is now locked in place and ready to use.