If I already have access arrangements approved by my school, can these apply to the UAT-UK tests?

Pearson VUE and UAT-UK statement on data breach here.

If you need a bursary or access arrangements, please apply and wait for confirmation before selecting your test.

Yes, if you are entitled to access arrangements during school exams, such as extra time, then you should be able to get this approved by UAT-UK. You will need to provide supporting evidence when applying for any access arrangements.