Try and scale down Barking police headquarters (3,8,4)

I believe the answer is:

new scotland yard

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'police headquarters' is the definition.
'New Scotland Yard' can be an answer for 'police' (headquarters of the Metropolitan Police). I'm unsure of the 'headquarters' bit.

'try and scale down barking' is the wordplay.
'barking' is an anagram indicator ('barking' can informally mean mad).
'try'+'and'+'scale'+'down'='tryandscaledown'
'tryandscaledown' is an anagram of 'NEW SCOTLAND YARD'.

Can you help me to learn more?

(Other definitions for new scotland yard that I've seen before include "police HQ" , "A place for pigs!" .)

I've seen this clue in The Times.

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