Another bloody stupid question from Rowums

Ok, this is going to be another stupid question, asked by me completely innocently. At the moment I am currently only in the Army's application process. When dealing with the staff at the recruitment centre I stick to addressing them as Sir, but so far have only dealt with men.
My question is; When in the Army (or indeed when talking to recruitment staff) what are women to be addressed as? Do I use Sir or possibly ma'm?

Thanks it's just that I don't want to get it wrong and look like a tit.

P.s I am well aware of the irony of trying to avoid looking like a tit by making myself look like a tit with this post :D

It's just good manners regardless. Don't use 'Miss' or 'Ms' - big poo trap.

Edited to add: There's no such thing as a 'stupid question' - just a question that isn't asked in the first place.