Having stopped work to eat bananas (3,2,5)

I believe the answer is:

out to lunch

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'bananas' is the definition.
(I've seen this in another clue)

'having stopped work to eat' is the wordplay.
'having stopped work' becomes 'outto' (I can't explain this - if you can you should believe this answer much more).
'to eat' becomes 'lunch' (lunching is a kind of eating).
'outto'+'lunch'='OUT TO LUNCH'

Can you help me to learn more?

(Other definitions for out to lunch that I've seen before include "unhinged?" , "Temporarily removed from office" , "unbalanced" , "being served in restaurant perhaps" , "Crackers" .)

I've seen this clue in The Everyman puzzle in The Observer.

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