Historic tax collection arrangement - then it goes wrong - lawyers brought in (5,4)
I believe the answer is:
tithe barn
'historic tax collection arrangement' is the definition.
(historical building for holding tithes)
'then it goes wrong lawyers brought in' is the wordplay.
'goes wrong' indicates an anagram.
'lawyers' becomes 'bar' (the bar can mean the legal profession).
'brought in' indicates putting letters inside.
'then'+'it'='thenit'
'thenit' is an anagram of 'tithen'.
'tithen' placed around 'bar' is 'TITHE-BARN'.
(Other definitions for tithe barn that I've seen before include "tax shelter?" , "large food store" , "historic building?" , "old building" , "Archaic construction" .)