Cancelling A level subjects - how late can schools do this?

[circular]

Concerned for DD1 who has 2 less popular choices.

How late can schools leave it to decide they are not running a subject previously offered?

Dd1 has just been told 2 of her A level choices are not running at current school due to low take up. Not a big deal, as she has other places, and would have been leaving anyway.

BUT as one of the subjects is Music, which she wants to study at University, it had made me question if other schools where she is holding provisional places may not run it.

I understand subjects may not run if not viable, but her school has always run Music in the past, even with just 2 or 3 pupils.
Is it possible that a subject can get pulled as late as enrolment day?. After all, that's when they know more reliable numbers. By then, its too late to go with second choice as they both want that result slips by 2 or 3pm on results day

Or even worse, turning up on the first day of term to be told its been pulled?

I know some Music degree courses accept Grade 8 theory in place of A level, which she will probably do anyway, but far from ideal.

[mummytime]

If you have a sixth form college that has say 1000 pupils just doing A'levels then they can run a wider range of courses than a school sixth form with 200. The tutor groups don't have to be bigger, and class sizes don't either, you just run more of them. The problem of sixth form colleges is they know their students less well, and some students can struggle with a lack of pastoral care (if only at the start).
However Music is not a subject that my DCs sixth form even struggles to put on. They do share some less popular A'levels wi the local Catholic school, eg. law.