Clue: He's not troubled with tumult in a little margarine spread (6,7,4,2,3,5)
Answer: BUTTER WOULDN’T MELT IN HIS MOUTH
Explanation: He's not troubled with tumult in a little margarine spread (6,7,4,2,3,5)
An anagram ('spread') of 'hes not troubled with tumult in' plus M ('a little **M**argarine'), with I suppose what is intended as an extended definition, but I think it is rather flaky.