Woofer glad don rebuilt after fresh start (12,3)

I believe the answer is:

newfoundland dog

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'woofer' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'glad don rebuilt after fresh start' is the wordplay.
'rebuilt' indicates an anagram.
'after' says to put letters next to each other.
'fresh' becomes 'new' (synonyms).
'start' becomes 'found' (I've seen this before).
'glad'+'don'='gladdon'
'gladdon' is an anagram of 'landdog'.
'new'+'found'='newfound'
'landdog' after 'newfound' is 'NEWFOUNDLAND DOG'.

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I've seen this clue in The Daily Express.

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