No herons _____ to be seen? Never mind (2,7)

I believe the answer is:

no regrets

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

'seen? never mind' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'no herons to be' is the wordplay.
'herons' becomes 'egrets' (egret is a kind of heron).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'be' becomes 'r' (I am not sure about this - if you are sure you should believe this answer much more).
'egrets' after 'r' is 'regrets'.
'no'+'regrets'='NO REGRETS'

Can you help me to learn more?

I've seen this clue in The Independent.

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