Polish school monitor Roedean's head sent down (7)
I believe the answer is:
perfect
'polish' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for perfect that I've seen before include "Without blemish" , "Exemplary" , "Past tense; ideal" , "Complete" , "Flawless - finish" .)