No worries.
The school can issue you an invoice I guess but if you don't pay it there is nothing they can do without passing it over to the local authority. Under the education act it's only the local authority that can prosecute for non school attendance (which is the next step after an unpaid fine). So a school issuing you a fine is basically unenforceable. A headteacher has the discretion whether to authorise any absence or not and we can advise and guide them in this decision but we can't overrule it. But any legal action is solely the decision of the LA, having said that we wouldn't usually prosecute if the school didn't want that. So if your school are saying they issue fines I would suggest having a chat to your LA and asking them what the process is. You could also check the schools attendance policy.
You cannot lose your place just from being absent. Many schools believe that they can take children off the roll after 4 weeks absence however this isn't actually lawful in accordance with the (statutory) guidance and they can only do this if they have also reported the pupil missing to the LA, and BOTH the school and LA have failed to locate the pupil. In your case this wouldn't apply as if they tried to locate you they would find you at your home address and you would say you were keeping the child off until the scary pandemic is less serious.
However, this does depend slightly on how "on it" your local LA are with the guidance and some may not challenge a school withdrawing a pupil incorrectly. At a later date you could quote the DFE statutory guidance at the school as if they take pupils off roll unlawfully then if you sued, they would be acting outside of the law however this would be a difficult challenge for a parent to take up with a school.
For anyone, my best advice now is to speak with your schools headteacher and be honest about the reasons you don't want your child in school. They may be willing to authorise a period of absence, we suggest putting an end date on it so it doesn't drag on indefinitely. Would also suggest sending a copy of a shielding letter belonging to a family member of this is the reason you don't want the child to return to school.
If the school authorise the absence, fine.
If they don't, it is only really meaningful if the LA are considering a fine. Most LAs are not issuing fines to parents where there is a genuine concern at the moment.
Finally my advice would be to also remember that the fine is like a speeding fine, an opportunity to pay a fixed penalty notice without going to court. You have the option to not pay the fine, and be prosecuted for the offence of non school attendance instead. This sounds very scary indeed, but would be your chance to go to court and present your reasons to a bench of impartial magistrates.
That's of course if the LA wanted to pursue with court, given the huge costs incurred to them. That's also if the LA solicitors agreed it was in the public interest. And if you did get as far as court, having been present in many many court hearings for non school attendance, I don't believe that magistrates are going to throw the book at people keeping their child off in a badly managed pandemic when there is someone clinically vulnerable in the home, or even if there isn't as well. My best guess that if anyone was prosecuted the outcome is most likely to be a conditional discharge for those cases genuinely with a good reason (CEV person at home in the house). However it would be prudent to be able to prove to the court that you had attempted to speak with the head teacher and LA first and gain their authorisation of the absence, so I would suggest doing everything in writing.
To be very honest I highly doubt there will be many prosecutions if any.
I hope this helps.