I don’t think so. Just like the TuneIn Radio icon. 

If I go to Service Settings and highlight TuneIn then I’m offered a ‘remove’ option - whether it works or not I don’t know, as I may at least have some use  for it. However, the Sonos Radio doesn’t even appear as a service.

It’s just confusing, as some people say that they did get rid of it at one time (but maybe that changed in later software versions). Others say that you can delete it once you’ve authorised it, but I’d rather not do that unless I know that method actually works.

I hear you. And I’d forgotten that they’d added the whole ‘remove TuneIn’ feature when they added the Sonos  Radio in the controller. Unfortunately, I’m not at home to test for you, as I’m not a Sonos  Radio  subscriber either, and have no intention of becoming one. 
 

Edit: why, suddenly, is my iPhone changing Sonos  to Sonia every time, when I have Sonos in my shortcuts in iOS. Very frustrating.