Batty as her poem signals (9)

I believe the answer is:

semaphore

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'batty as her poem signals' is the definition.
I can't judge whether this definition defines the answer.

'batty as her poem' is the wordplay.
'batty' indicates anagramming the letters.
'as'+'her'+'poem'='asherpoem'
'asherpoem' anagrammed gives 'SEMAPHORE'.

Can you help me to learn more?

(Other definitions for semaphore that I've seen before include "Old communications system" , "See arm hop in signalling system" , "Signalling apparatus" , "Messaging by flags" , "Way to signal" .)

I've seen this clue in The Independent.

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