Part-time school (half-class bubbles) for all years for now, full-time for everyone in September. If there are not enough classrooms, use currently vacant facilities like church halls, sports venues etc. (but make it clear that parents will be responsible for getting their kids there).
Classes in rows, chalk and talk teacher style, bit boring but OK and will stop kids falling behind while slowing virus spread. For playtime, let kids play normally as long as they are outside. EVERYONE needs to be wearing masks and teachers should have face shields as well. (No masks for kid when playing outdoors though). Get manufacturers to ramp up production fast. They have done this in other countries. In China and Taiwan, once it became clear to manufacturing companies that mask wearing would allow them to open up production (and minimize losses) faster, this incentivized them to divert production lines to making masks and face shields.
Get numbers down fast over the summer through compulsory masks (medical needs/disabilities excempted) in public places, aggressive test-and-trace, and centralized quarantine in empty hotel rooms.
All schools need to offer proper provision to all pupils while blending learning is going on. I know most schools are doing a great job, but a minority are not. This is not OK. Professionals need to be doing their jobs. All professionals, not just 85% of them. Roll out centralized curriculum provision where it's already available, so that teachers do not have to reinvent the wheel and can devote their time to reviewing kids' work and giving feedback/extra practice resources if it is evident that a child needs to work on a particular more or hasn't understood a particular point.
Keyworker kids should stay in separate bubbles for the moment, but they need to be getting an education. Give out the schoolwork packs being sent out to kids with no home PC and make sure they have set hours for working through these when at school. Again, most schools are doing this already but a minority are just babysitting the keyworker kids and doing craft activities with them.