I believe the rules are to self isolate if you have had contact with someone with Covid within 48 hours of their symptoms starting. I guess the question is do you count in actual hours or just days.
Taught a child on Friday until 3.30pm.
6.30pm Sunday night child starts with being unwell.
Technically 51 hours later?
My thoughts are that I should. But actually me and the whole class for that matter have had a clear 51 hours before the first symptom.