Follow up to BMW suspension query

[888sp3]

I've decided to go with the BMW option. As a final check can somebody please measure the following:
Outside of Sierra brake drum cover to opposite side ( i.e. width of rear wheel inside faces)
The dimensions of the Sierra diff to make sure that the BM item will fit into the chassis without alteration.
Again thanks for any assistance.
Finally anybody got contact with "Rugby builder" who left a message for me in June which due to me not using the forum I missed and hes not replied to my grovelling apology?