Excluding top royal commentator (5)

I believe the answer is:

noter

I'm a little stuck... Click here to teach me more about this clue!

'commentator' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'excluding top royal' is the wordplay.
'excluding' becomes 'not' (I've seen this in another clue).
'top royal' becomes 'er' (abbreviation for Elizabeth Regina. I am not sure about the 'top' bit.).
'not'+'er'='NOTER'

Can you help me to learn more?

(Other definitions for noter that I've seen before include "He jots things down" , "One observes" .)

I've seen this clue in The Guardian.

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