Drop a line to one of those always on hand or available in the convenience store
I believe the answer is:
fishfinger
'the convenience store' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I don't see?
'drop a line to one of those always on hand or available in' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
'in' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for fishfinger that I've seen is " snack food".)