What BMWs use the Caterham BMW diff?

[rotorwings]

As the title says really: what model(s) of BMW use the diff that Caterham are supplying in their cars/kits?

Specifically, I am trying to working out what is in my 2012 R300 (open diff). It is being replaced with a Quaife ATB next week.

[Dr Slotter]

I've never find a conclusive answer, but as far as I can tell they are from a E8x 1 series. I've also seen reference to them being in some 3 series of similar vintage.