I'm not a beetle expert, but a quick scour of the internet hasn't told me about any blue beetles which are a pest of roses. I suspect it may just have landed there from somewhere else... there's a blue beetle which lives on fuchsias, and another which inhabits alder trees. In addition there's now the blue mint beetle, newly arrived from the continent, I think, which eats mint (now there's a surprise!) but isn't considered a serious pest. So unless someone (eg @wild edges) with better knowledge than mine thinks otherwise, I'd just admire it.
Since 2019 I've lived in east Clare, in the west of Ireland.
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It's a pretty colour, whatever it is.