Busy breaking the novice in (8)

I believe the answer is:

bustling

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'busy' is the definition.
(synonyms)

'breaking the novice in' is the wordplay.
'breaking' becomes 'busing' (I can't explain this - if you can you should believe this answer much more).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'novice' becomes 'L' (as in a learner driver with L-plates on their car).
'in' means one lot of letters goes inside another.
't'+'l'='tl'
'busing' enclosing 'tl' is 'BUSTLING'.

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(Other definitions for bustling that I've seen before include "busy" , "Acting fussily" .)

I've seen this clue in the Evening Standard.

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