Don't insult the Sgts' Mess Member being dined out by wedging your boss into someone elses night. Say farewell to your BC separately at his own. This doesn't have to be the whole Mess dining him out, you can just have the Bty seniors present, maybe with their Doris' to bump up the numbers. Take a Bty second looey too, he can be Mr Vice.
The Bty can dine him out, his (Orificer) mess can dine him out, but unless he is LE he has no right to be dined out of the Mess. (He can't be dined out of a mess if he has never been a member of that mess)