Do parade-ground manoeuvre in shop demo? (12)

I believe the answer is:

countermarch

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'do parade-ground manoeuvre' is the definition.
I can't judge whether this definition defines the answer.

'shop demo?' is the wordplay.
'shop' becomes 'counter' (I am not sure about this - if you are sure you should believe this answer much more).
'demo?' becomes 'march' (demonstration).
'counter'+'march'='COUNTERMARCH'

'in' acts as a link.

Can you help me to learn more?

I've seen this clue in The Irish Independent.

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