Not up for Enid Blyton's first novel? (2,3)
I believe the answer is:
in bed
'not up' is the definition.
(I've seen this in another clue)
'enid blyton's first novel?' is the wordplay.
'blyton's first' becomes 'b' (1st letter of 'blyton').
'novel?' indicates anagramming the letters (letters in a new or novel order).
'enid'+'b'='enidb'
'enidb' with letters rearranged gives 'IN BED'.
'for' is the link.
(Other definitions for in bed that I've seen before include "Lying, possibly" , "Retired?" , "10 [AT REST] ," , "Not yet up" , "as 15 Down [GARDENERS] may be?" .)