Henry IV of England's chamber (4)

I believe the answer is:

hall

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'chamber' is the definition.
(I know that hall is a type of chamber)

'henry iv of england's' is the wordplay.
'henry' becomes 'hal' (short for Henry).
'iv of england' becomes 'l' (I can't explain this - if you can you should give a lot more credence to this answer).
'hal'+'l'='HALL'

Can you help me to learn more?

(Other definitions for hall that I've seen before include "Large house (linked to Dotheboys, Wildfell and Toad)" , "Large public building" , "See 1" , "Chamber" , "Auditorium" .)

I've seen this clue in The Independent.

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