Your link is secured, i.e. it has the 's' in https
https://radiocaroline.co.uk/#home.html
If I just start typing radiocaroline in the address bar it takes me to an unsecured server, no idea why, or why it has only just started doing that and displaying the site in mobile phone style.
http://www.radiocaroline.co.uk/#home.html
Something weird, those suggestions fix 99% of problems on a default set up, if you have something non-standard, maybe some extensions installed, an adblocker for example, they can cause display issues. It's odd though to be served the mobile version on a desktop, I think the addresses are the same and the browser determines which version you get. This is what I have in the address bar
https://radiocaroline.co.uk/#home.html