What’s found in pub that’s up for restoration (5)
I believe the answer is:
rehab
'restoration' is the definition.
(I've seen this before)
'what's found in pub that's up' is the wordplay.
'what' becomes 'eh' (sound used to ask 'what?' or 'pardon?').
'found in' is an insertion indicator.
'pub' becomes 'bar' (both are drinking establishments).
'that's up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'bar' reversed gives 'rab'.
'eh' going into 'rab' is 'REHAB'.
'for' is the link.
(Other definitions for rehab that I've seen before include "Treatment for dependency" , "Alcohol clinic" , "remedial treatment" , "Health-restoring process" , "Treatment for alcohol abuse" .)