Uniform relative put on good for church service (8)
I believe the answer is:
evensong
'for church service' is the definition.
(I've seen this before)
'uniform relative put on good' is the wordplay.
'uniform' becomes 'even' (both can mean equal or level).
'relative' becomes 'son' (son is a type of relative').
'put on' is a charade indicator (letters next to each other).
'good' becomes 'g' (abbreviation).
'even'+'son'+'g'='EVENSONG'
(Other definitions for evensong that I've seen before include "6 [SERVICE] ?" , "Church service late in the day" , "Late afternoon church service" , "Anglican service" , "Service of evening prayer in Church of England" .)