Does the UK have Cash App? That’s what I use. And it usually lets you make payments in bitcoin straight from the app.
To get a little more complicated there may be some vendors that dash app refuses to sen to so what you would do is download a bitcoin wallet on your phone.. something simple. I use MUUN and can use Cash App to transfer all my BC ro MUUN and now use said app to make purchases.
A simple yet confusing If you don’t know much about about bitcoin.
Cheers!