Peach skins served up for rest (6,5)
I believe the answer is:
beauty sleep
'rest' is the definition.
(I have seen 'Refreshing rest' mean 'beauty sleep' so perhaps 'rest' could also mean 'beauty sleep')
'peach skins served up' is the wordplay.
'peach' becomes 'beauty' (both can mean an excellent example of something).
'skins' becomes 'peels' ('peel' can be a synonym of 'skin').
'served up' shows that the letters should be reversed in order (in a down clue, letters go up).
'peels' backwards is 'sleep'.
'beauty'+'sleep'='BEAUTY-SLEEP'
'for' acts as a link.
(Other definitions for beauty sleep that I've seen before include "to bed early for this" , "Rest needed to keep one looking young?" , "Refreshing rest" , "What we all need at night to look our best" , "Slumber before midnight" .)