Hit penned by gross, boorish Aussie musician in the 70s? (4,6)

I believe the answer is:

glam rocker

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'aussie musician in the 70s?' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'hit penned by gross boorish' is the wordplay.
'hit' becomes 'lam' (to 'lam' means to hit hard).
'penned by' indicates putting letters inside (inserted letters are penned in).
'gross' becomes 'gr' (abbreviation).
'boorish' becomes 'ocker' (I've seen this before).
'lam' going within 'gr' is 'glamr'.
'glamr'+'ocker'='GLAM ROCKER'

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I've seen this clue in The Times.

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