Advantage of Cockney's reported plan when visiting pub? (5)

I believe the answer is:

avail

'advantage' is the definition.
(thesaurus)

I can't explain the rest of the clue.

(Other definitions for avail that I've seen before include "See 3" , "Medal (informal)" , "(Of no) use or benefit" , "Be of help or advantage" , "Be of service to" .)

I've seen this clue in The Independent.

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