Working with the Church in former times (4)
I believe the answer is:
once
'in former times' is the definition.
(I've seen this before)
'working with the church' is the wordplay.
'working' becomes 'on'.
'with' is a charade indicator (letters next to each other).
'the church' becomes 'ce' (abbreviation for Church of England).
'on'+'ce'='ONCE'
(Other definitions for once that I've seen before include "in bygone days" , "One-time musical film and song" , "Formerly; as soon as" , "not repeatedly" , "In times past" .)