Furniture seen on more than three hoardings?

I believe the answer is:

four-poster bed

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'more than three hoardings?' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'furniture seen on' is the wordplay.
'furniture' becomes 'fourposter' (four-poster is a kind of furniture).
'seen on' becomes 'bed' (I am not sure about this - if you are sure you should believe this answer much more).
'fourposter'+'bed'='FOUR POSTER BED'

Can you help me to learn more?

I've seen this clue in The Telegraph.

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