Most things at the shop are paid for in cash. Usually at the filling station too. And the pub. It's basically household bills that get cheques and Net mail order, card. Cash allows one to see the money going and concentrates the mind on whether one should purchase or not. Those who don't tend to use it lose that useful reminder.
Yes 10p is common. You must just tend to purchase items that require only 50p/20p and copper in change.
I only use cash for the launderette, for the burger van up the road and for some car parks and supermarket trolleys. I use plastic for everything else.
I've got just 2 coins in my pocket at the moment, one 5p and one 10p.