Model number is QDF13N ...so that's the one. Birds Auto was a bit cheaper, 950 GBP or something like that.
Quaife arrived and happily the ring gear is going to bolt right up. Dimensionally it seems identical to the BMW diff carrier.
Instructions call for heating the ring gear to 100C in boiling water, then installing it. I may stick it in the oven for an hour or two at 150F as I don't have compressed air to blow the bolt holes and threads out. Then red Loctite, 100 NM, plus another 30 degrees on the 10 bolts.