I wouldn't venture to say what is "correct"! It could be argued that the new kitchen will be a benefit to you that could, with enough effort, be valued. Or it could be argued that the benefit is too tenuous to count as pecuniary.
In the days of the Standards Board for England, I have seen a ruling that members of the committee of a charitable body seeking a decision from the council to grant a lease were deemed to have been incorrect to remain in the meeting and vote. Although no action was deemed necessary, and the decision still stood (even though it would have gone the other way had the councillors not voted).
However, I'd be tempted to say that considerations of this kind are nowadays mostly academic. It seems perfectly clear that your involvement with the council decision would be exceedingly unlikely to trigger a criminal prosecution. Apart from that, the rules have no teeth now, and Standards Officers are anyway reluctant to get involved in borderline cases of minimal value.
If you pressed me for an answer, I think personally I would err on the safe side and withdraw from the discussion and vote, perhaps after making the case in favour of the planning permission. The council is anyway only a consultee, and will be ignored unless it offers substantive planning considerations for or against the application. Opinions don't count!