Has a flirtation - and doesn't stop at that (7,2)

I believe the answer is:

carries on

I'm a little stuck... Click here to teach me more about this clue!

'has a flirtation and doesn't stop at that' is the definition.
I can't tell whether this defines the answer.

'has a flirtation and' is the wordplay.
'has' becomes 'carries' (carrying is a kind of having).
'a flirtation' becomes 'o' (I can't justify this - if you can you should believe this answer much more).
'and' becomes 'n' (common abbreviation for 'and').
'carries'+'o'+'n'='CARRIES ON'

Can you help me to learn more?

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app