Annual return adopted by bank on only a few occasions (6)
I believe the answer is:
rarely
'only a few occasions' is the definition.
I can't tell whether this defines the answer.
'annual return adopted by bank on' is the wordplay.
'annual return' becomes 'ar' (this could be a standard abbreviation I've not previously seen).
'adopted by' is an insertion indicator (I've seen this in other clues).
'bank on' becomes 'rely' (I've seen this before).
'ar' placed inside 'rely' is 'RARELY'.
Can you help me to learn more?
(Other definitions for rarely that I've seen before include "Not very often, seldom in fact" , "Seldom, not frequently" , "Very occasionally" , "very well" , "when hundred-to-one horse wins?" .)