Meh, of all the covid rules shopping in pairs/groups in the most ridiculous. It doesn't protect anyone, it just means the supermarkets can fit more trolleys in so take more money in a shorter space of time. The only thing it impacts to customers is if it is busy, you might have to queue outside.
If the store can fit 75 people and there are 20 couples in that 75, that's actual trolleys reduced by 20. That's why supermarkets want you to shop alone.
If the store can fit 75 people safely, and there are 60 people in and 20 of them are in couples the store is still secure.
If I go with dh I am in and out quicker than if I go alone. Plus it makes life easier as we both cook so not relying on the other to get what we want. Dh pushes the trolley and gets the heavy stuff. I get to go up and down aisles and nip back for forgotten things without dragging the trolley around. Plus tbh, I spend all week with just the kids for company, I like shopping on a Saturday morning for naice bits for the weekend with DH. The kids stay home as they hate shopping.
Honestly, life is shit and dark and depressing enough as it is. If you worry about safety click and collect, shop when it's quiet, get a delivery. I follow all the actu laws and most of the guidance. I wear a mask, maintain 2m, wash my hands. But unless there are massive queues it makes no difference if its 1 per trolley or more.