@sgunhouse Thanks for the suggestion. I always use a VPN, but not the one in Opera - I use Freedome which, although a subscription service, seems very stable and works across the iMacs and iPads.
TuneIn worked through Chrome and safari so it wasn't my VPN per se which was the problem. Nor, it seems, was it a problem with Opera and Freedome as when following your suggestion, I launched Opera specifically to check the Preferences and my "Home" page opened - to TuneIn Radio! Something (and certainly not knowingly anything that I have done) has changed!
Opera's version number is the same as I posted in the top post.