Yeah that's the one, Quaife from the UK make it, they call it an ATB (automatic torque biasing) diff, so similar to torsen.
I got it through Palmside http://www.palmside.co.nz/ in NZ, he (Deane) ordered it in and then posted it to me in Newcastle, very easy.
I had a diff shop fit it, they had to bugger around a bit with shims setting the backlash, but all went together good.
So far I have taken it around Wakefield park, and it seemed great, great traction and very smooth. Going in a hillclimb this weekend so will see how it goes around tight twisty stuff.