As others have said, for most, going getting your results is a rite of passage (yes, some people don't care, but then some people don't care about a lot of things, doesn't mean those who do are wrong, and the ops dd has said she'd prefer to be there, so does care). But more importantly, she needs to be able to access staff help if things have gone wrong.
I would be reluctant to leave her home alone because if her grades go badly wrong, she'll need someone to help her navigate colleges/school 6th form requirements, appeals etc, having you, or another adult there could be crucial, and she'll need emotional support- failed exams seem like the end of the world at the time.
On the other hand, if it all goes right, an empty house on results night? Party at yours for the whole year then!
If you can't find another week you can go away with these other friends then this year it's a no. Do something else for your family holiday. Even a wednesday-Wednesday so you get back the night before.