Church expert accepts regularly using note in musical form (8)
I believe the answer is:
chaconne
'note in musical form' is the definition.
The definition suggests a singular noun which matches the answer.
'church expert accepts regularly' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'expert' becomes 'ace' (ace is a kind of expert).
'accepts' is an insertion indicator.
'regularly' becomes 'onn' (I am not sure about this - if you are sure you should believe this answer much more).
'ace' placed around 'onn' is 'aconne'.
'ch'+'aconne'='CHACONNE'
'using' is the link.
Can you help me to learn more?
(Other definitions for chaconne that I've seen before include "Slow dance" , "Stately dance" , "Music for Spanish dancing" , "Composition" .)