The return to school is going to be incredibly complicated. Given the level of vagueness that schools were given about closing, I am not confident that they will make any decision on how to deal with the huge gap in children's skills and knowledge that will have opened up.
It's going to hugely widen the gap between poorer and richer pupils (poor kids can work at home, though this is restricted if their home is overcrowded, chaotic or if they lack a computer or Internet connection). Some children will have suffered real neglect, and others will have lost loved ones in quite stressful circumstances.
The current curriculum from y1-y9 is all about a progression of skills from year to year, so adaptations will need to be made if children just turn up in September without having completed half of their previous year. This could be dealt with on a holistic level by the government, but I doubt it will be and so individual schools or teachers will need to work out how we're going to cover 1.5 years in 1. Opening longer and setting homework won't work because teachers can't just work more at the same quality, and because that's not how children learn. They need time to process and revisit things. Finally, I'm pretty sure that the teacher crisis will be further intensified by this crisis. Trainee teachers are all passing, but they aren't all ready, so some teachers will have the skills to teach effectively. Some other teachers won't return, but children will.
It's all a bit of a headache, but I wouldn't expect or want the government to be working on this in the short term, as there are so many pressing concerns. I, however, clearly have nothing better to think about!