Badger-hunter knowing trail around Australia

I believe the answer is:

sausage dog

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'badger-hunter' is the definition.
I can't judge whether this defines the answer.

'knowing trail around australia' is the wordplay.
'knowing' becomes 'sage' (I can't explain this - if you can you should believe this answer much more).
'trail' becomes 'dog' ('dog' can be a synonym of 'trail').
'around' is an insertion indicator.
'australia' becomes 'aus' (abbreviation).
'sage'+'dog'='sagedog'
'sagedog' going around 'aus' is 'SAUSAGE-DOG'.

Can you help me to learn more?

(Other definitions for sausage dog that I've seen before include "Dachshund (colloq.)" , "At a stretch, a pet" .)

I've seen this clue in The Telegraph.

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