Quote Originally Posted by series3 View Post
So, if i do manage to get my hands on a mcnamara bolt-operated diff locker, i should look into some more heavy duty axles to go with it? is the rover centre on the SWB series III up to the challenge?

This is all new to me, having only had the old girl for about six months and just looking into things now.

thanks everyone for your input, its awesome to have this kind of knowledge on tap for a novice
If you have a (stock) SWB, then you have a rover diff with 1.1" diameter 10 spline axles. According to cmurray above, the (rover) mcnamara has 1.24" 24-spline axles, which is the same as the later model stuff.

He says he has a rover-type. So it would fit your vehicle.