In Denmark, Sweden, Norway, Finland the same shop would have a phone number. You type the phone number into the app (which shows the name as confirmation), the amount, and press send. It's not tied to any particular bank.
Unfortunately, the UK system isn't really catching on. Instead, my friends seem to be using proprietary apps which only work for friends at the same bank.
There's also a self service rest stop mainly for cyclists that's been in operation for the last 10 years or so, between Woodside and Half Moon Bay.