Beat up a Liberal in old province (5)
I believe the answer is:
natal
'old province' is the definition.
(former South African province)
'beat up a liberal' is the wordplay.
'beat' becomes 'tan' (tan can mean to beat or hit).
'up' is a reversal indicator (in down clue: letters go upwards).
'liberal' becomes 'l' (abbreviation).
'tan' written backwards gives 'nat'.
'nat'+'a'+'l'='NATAL'
'in' is the link.
(Other definitions for natal that I've seen before include "Brazilian port" , "of an ass?" , "old province" , "Relating to birth - former South African province" , "Of birth; former African republic" .)