Row about Liberal alternative to Thatcher? (5)
I believe the answer is:
tiler
'alternative to thatcher?' is the definition.
(tiling a roof is an alternative to thatching it)
'row about liberal' is the wordplay.
'row' becomes 'tier' (a tier is a row of things).
'about' is an insertion indicator.
'liberal' becomes 'l' (abbreviation).
'tier' placed around 'l' is 'TILER'.
(Other definitions for tiler that I've seen before include "doorkeeper at lodge" , "Craftsman" , "Roofer" , "Relit for tradesman" , "Masons' doorkeeper" .)