An excellent position in the theatre (3,4)

I believe the answer is:

box seat

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'the theatre' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?

'an excellent position' is the wordplay.
'an excellent' becomes 'box' (I am not sure about this - if you are sure you should believe this answer much more).
'position' becomes 'seat' (seating is a kind of positioning).
'box'+'seat'='BOX-SEAT'

'in' acts as a link.

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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