Confused...isolation advice from school

[Hmm12121]

The child who my child sits next to in tutor for 25 mins every day has tested positive for Covid. My child last sat next to him on Friday and he developed symptoms on Monday. School originally said my child would need to self isolate for 14 days but is now saying he doesn’t need to self isolate at all. Is this correct?
I know if my child develops any symptoms then we all need to self isolate immediately but how do the know how long a child is asymptotic for?

My sons class have just been sent home.
Confirmed case in their class.
Anyone that could have been in direct contact with infected child for 15 minutes needs to isolate for 14 days. Family members do not.

If he didn't sit next to him at all on Monday then I think it's correct yes. The gap between Friday morning and Monday morning is 72 hrs, so in excess of the 48hrs test & trace look at.

Yes I think it is the gap in contact that avoid isolation, because his symptoms didn’t start until Monday so more than 48 hours since they were in contact

They look at contacts in the last 48 hours of symptoms starting so if symptoms started on Monday he would only need to isolate if he'd been in contact on Saturday.

Child wasn’t in on Monday. So yes it would have been 72 hours. So school are correct.
Not sure I buy the 48 hour thing really but the rules are the rules. My colleague came down with a cold on Monday and I’m only just feeling like I may be too.
Anyway, told my child to be extra vigilant and actually tell me if he has a headache, cough, sore throat (that was main symptom of positive test child) etc.