Pupils in nearby comprehensive (3-5)
I believe the answer is:
all-round
'comprehensive' is the definition.
(I've seen this before)
'pupils in nearby' is the wordplay.
'pupils' becomes 'LL' (two abbreviations for 'learner').
'in' means one lot of letters goes inside another.
'nearby' becomes 'around' (synonyms).
'll' put within 'around' is 'ALL-ROUND'.
(Other definitions for all-round that I've seen before include "General, not specialised in ability" , "Including; complete" , "Comprehensive" , "A doll run (anag.)" , "Applying to everything" .)