Advertisement space needed, observe the directors (11)

I believe the answer is:

noticeboard

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'advertisement space' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'observe the directors' is the wordplay.
'observe' becomes 'notice' (noticing is a kind of observing).
'the directors' becomes 'board' (board of directors).
'notice'+'board'='NOTICEBOARD'

'needed' is the link.

Can you help me to learn more?

(Another definition for noticeboard that I've seen is " that displays information".)

I've seen this clue in The Irish News.

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