Novelist introducing last letters from Fanny Brawne in Time Out (4-3)
'time out' is the definition.
(term for sleep - time spent unconscious or 'out')
'novelist introducing last letters from fanny brawne' is the wordplay.
'novelist' becomes 'shute' (novelist Nevil Shute).
'introducing' is a charade indicator (letters next to each other).
'last letters from' says to take the final letters.
The last letters of 'fanny brawne' are 'ye'.
'in' acts as a link.
(Another definition for shut-eye that I've seen is "Sleep".)