For many children, the symptoms will be relatively minor. Unless your child has underlying health problems or you have circumstances which mean relatives would be more at risk then there is absolutely no reason to keep your children off school. It’s actually better for them to be at school and catch it as they will be back to business sooner rather than later. They will also then be immune.
I can’t say I am entirely comfortable with the government policy of sacrificing a few to save the majority which is essentially what they are saying, but for the first time in my life my biology degree is actually proving quite useful. I do worry about those most at risk being put more at risk by current policy. However, the government are right in trying to get as many people not considered at risk as infected as possible. If you have vulnerable people in your family though I would be doing everything I could to protect them until 6-12 months time when a vaccines is available.
School closures are like a tap - they can easily turn them on and off. If children are at school and infecting each other then on the whole symptoms will be mild and they are off for 7 days. They may well infect adults in the household but this should be manageable I.e. you’re expecting it. Keeping all children at school helps manage where they are as normal routine ensues. Keeping them open means parents don’t have to rely on childcare from older relatives which can lead to further spread to those people we need to protect. Remind yourself that this is not about protecting yourself but about protecting the most vulnerable.
We are of course reliant on statistical modelling to get things right which is also a concern. We also assume that British people will cope with isolation for 2-4 weeks. After that people will think they know best and start leaving their homes. That’s not science, that is just behaviour. We are not China where if you don’t do what your told you disappear. Lockdown situations need to be implemented when the most vulnerable are at greatest risk.
I can honestly see schools closing for four weeks over Easter but then things will go back to normal (ish).
I have waffled a lot. To address your point - no schools shouldn’t close nor should children be kept off unless they have an underlying health reason.