Salvation Army church has uniform gravy (5)
I believe the answer is:
sauce
'gravy' is the definition.
(I've seen this before)
'salvation army church has uniform' is the wordplay.
'salvation army' becomes 'sa' (abbreviation).
'church' becomes 'ce' (abbreviation for Church of England).
'has' is an insertion indicator.
'uniform' becomes 'u' (phonetic alphabet: alpha, bravo, charlie etc.).
'sa'+'ce'='sace'
'sace' going around 'u' is 'SAUCE'.
(Other definitions for sauce that I've seen before include "sharp language" , "Cheek (sl.); ketchup" , "Dressing served with food" , "Food accompaniment" , "(Semi)liquid flavouring" .)