Rome excursion is extra (4)

I believe the answer is:

'is extra' is the definition.
(both can mean additional)

'rome excursion' is the wordplay.
'excursion' indicates an anagram (letters go on a trip or excursion).
'rome' anagrammed gives 'MORE'.

(Other definitions for more that I've seen before include "Additional or larger amount" , "Greater quantity or number" , "To a greater extent" , "victim of Henry" , "What Oliver wanted" .)

I've seen this clue in The Mirror.

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