The convenience of lads? (5)
I believe the answer is:
gents
I believe this clue is a double definition.
'the convenience' is the first definition.
(I've seen this before)
'lads?' is the second definition.
('gent' can be a synonym of 'lad')
'of' acts as a link.
(Other definitions for gents that I've seen before include "toilet" , "Men (colloq.)" , "Public convenience" , "Male loos" .)