Dick,
Bloody hell ... now my bodgey separation techniques are being used as NAS fodder!!
Okay, so I don't know up from down ... over in the west. However, even allowing for misplaced ocean, I don't think a 35nm diversion is likely. If it was, then let's step descend them both till the Tower can take over. Might cost him 50c extra??
Once Broome Control Zone is established, once Broome Tower is built, once a Controller has set up digs and once the procedures have been developed and once that Controller is rated ... ask that question again ... and you'll get the correct answer.... which I'm sure would be monetarily satisfactory.
BUT, say it was the proposed E above D ... would the answer be much different?