I can see why they want it, and it was done in other countries I believe.
I am shielded and I just don't see how it would work, the country is now back working, bars and stuff will open soon, when would the hour be. Not to mention the huge lack of empathy that has been shown towards the group (Just stay home, its not that hard! Umm yes it fucking is and its not that simple either but thats not a discussion to have here), it would be impossible to implement.
I go out for a walk at 6 in the morning, I see the same people each morning which is lovely, and we keep a distance. I did try a different time of day and it was a scary experience, lots more people, many not distancing, so I won't do it again.
What we need is a plan in place with stages of easing shielding, in comparison to infection rates, information on how the stopping of shielding will work as the situation progresses and what shielding will look like if a second wave occurs. I don't see how a shielding hour could work at all.