[MF] Too direct a clue there, Martha ! ;-)
Quick joky one : çontrol mechanism (6,6)

BTW, there is a definition for "Bust down reason" - it's not just a device. I can't tell if there is for "Case bust", which could just mean something that encases a bust ie. "Playtex Brassiere", which is wrong.

[MF] No. Slightly more amusing in a schoolboy humour sort of way.

[Blob] I think brassière would be clued as "Bust up reason (9)". [MF] "Case bust" wasn't meant to be a clue.

And the (7,9)??

[MF]Just an allusion to the clues I was commenting on. But if you can find a solution anyway, don't let me stop you! Am I anywhere on the right lines with my solution to "Bust down reason"?

Yes.