When they announced it, they specifically said supermarkets would be open and allowed to sell everything.
last time we had a mix. Boots veyr regulated, but you could go and get stuff, my impression was that all the regulation was there due to the pharmacy being swamped.
Asda etc closed the clothes for a couple of weeks, then i noticed it was open again. (I know because I needed to get knickers for dd). Range etc open to sell everything (still don't get why the Range is considered essential...)
Our M&S was only open for food too