Mistakenly alter a top building for self-catering guests (9)

I believe the answer is:

apartotel

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'for self-catering guests' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'mistakenly alter a top' is the wordplay.
'mistakenly' indicates an anagram.
'alter'+'a'+'top'='alteratop'
'alteratop' is an anagram of 'APARTOTEL'.

'building' is the link.

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I've seen this clue in The Times.

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