Battle to reach toilet after a drink? (8)
I believe the answer is:
waterloo
'battle' is the definition.
(I've seen this before)
'toilet after a drink?' is the wordplay.
'toilet' becomes 'loo' (loo is a kind of toilet).
'after' is a charade indicator (letters next to each other).
'a drink?' becomes 'water' (I've seen this before**).
'loo' after 'water' is 'WATERLOO'.
'to reach' is the link.
(Other definitions for waterloo that I've seen before include "Ultimate defeat - London station" , "Napoleon's final battle" , "Losers may meet theirs" , "battle in Belgium" , "Belgian village where Napoleon fell" .)