I used to work in an open plan office and the boss could see us from behind a glass partition. A colleague used to be a chatterbox, and if the boss was watching her manager used to say 'keep your head down Doris' and this has stuck but I also use it if I have reach over someone or pass something over someone's head.
Cutlery is diggers, from my Army days, as is dobie dust(washing powder).
What does surprise me is how some sayings seem to be disappearing. I've used two in work recently and no one under the age of 30 had any idea what I meant.
I had a school teacher (in the 1950's) who when looking at pupils work was often say"Goodness gracious galloping grasshoppers" and "Coo chase me round the cherry tree!" LOL.