Large ducks in the ladies perhaps (3)
I believe the answer is:
loo
'the ladies perhaps' is the definition.
(I've seen this in other clues)
'large ducks' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'ducks' becomes 'OO' (OO resembles two zeroes or 'ducks' in cricket).
'l'+'oo'='LOO'
'in' acts as a link.
(Other definitions for loo that I've seen before include "Ladies, perhaps" , "Privy" , "Lavatory - old card game" , "In which one goes" , "Toilet (informal)" .)