Excellent account, with documentation, about movement – vinegary stuff (6,4)

I believe the answer is:

acetic acid

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'movement vinegary stuff' is the definition.
I can't tell whether this defines the answer.

'excellent account with documentation' is the wordplay.
'excellent' becomes 'acetic' (I can't explain this - if you can you should give a lot more credence to this answer).
'account' becomes 'ac' (abbreviation for account).
'with' says to put letters next to each other.
'documentation' becomes 'ID' (identification documents).
'acetic'+'ac'+'id'='ACETIC ACID'

'about' acts as a link.

Can you help me to learn more?

(Other definitions for acetic acid that I've seen before include "Component of vinegar" , "pickling stuff?" .)

I've seen this clue in The Independent.

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