Worried at posh school report (5)
I believe the answer is:
eaten
'worried' is the definition.
(I've seen this before)
'posh school report' is the wordplay.
'posh school' becomes 'Eton'.
'report' indicates a 'sounds like' (homophone) clue.
'eton' sounds like 'EATEN'.
'at' acts as a link.
(Other definitions for eaten that I've seen before include "What's taken in" , "demolished, possibly" , "Consumed" , "used for food" , "Devoured" .)