Hear me out!
I don't think they planned to close schools when they did. I think the Welsh and Scotish governments forced their hand and they themselves were influenced by public opinion more than the science.
When I first heard "the plan" it sounded like there were terrible things to come but it made sense to me, as a way of controlling things as much as possible.
The public didn't like it and there was outrage that we didn't "lockdown" to protect ourselves, although "the public" also didn't behave in any sort of sensible manner to protect themselves as we saw last weekend.
So, measures were in force earlier than planned. The more restrictions there are and the earlier they are in place, the longer this thing will last. The restrictions don't protect "us", they protect the NHS. Most people will need to get it before this is over. Lockdown won't make it go away, just slow the rate of infection, meaning it takes longer to play out. While the NHS is coping, was there any need for the restrictions?
In Italy, it has taken 3 weeks for signs of social unrest to emerge. If that happens here we won't be even close to the peak at that stage. What happens then?