Could be mally- I thought constable was the most likely term but it was only 9- I never thought of the plural. I don't recall any other answers being plural though. Police magistrate doesn't feel right though- it's not a common term
I am also doing this quiz and Police constables is the best I've come up with, as I don't think we have lieutenants in England. If any one can help and sorry for jumping on your post "tatty1", but does anyone have the answer for No.22 The Prime Minister (7,5)