Drinking with army officer on ecstasy in part of Cambridge (7,7)

I believe the answer is:

downing college

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'part of cambridge' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'drinking with army officer on ecstasy' is the wordplay.
'drinking with' becomes 'downing' (as in downing a drink. I am not sure about the 'with' bit.).
'army officer' becomes 'col' (short for colonel).
'on' becomes 'leg' (cricket term, fielding positions).
'ecstasy' becomes 'E' (informal term for the drug).
'downing'+'col'+'leg'+'e'='DOWNING COLLEGE'

'in' is the link.

Can you help me to learn more?

I've seen this clue in The Times.

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