A crew injecting heroin on a mountain top? (7)

I believe the answer is:

aheight

I'm a little stuck... Click here to teach me more about this clue!

'a mountain top?' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'a crew injecting heroin' is the wordplay.
'crew' becomes 'eight' (an eight-person rowing team).
'injecting' is an insertion indicator.
'heroin' becomes 'H' (H is a slang term for heroin).
'a'+'eight'='aeight'
'aeight' placed around 'h' is 'AHEIGHT'.

'on' acts as a link.

Can you help me to learn more?

I've seen this clue in The Independent.

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