Just had another look at Freeview streaming app and still no way to exit properly yet and had a look at details thinking could uninstall and reinstall, but only option is to reinstall app, can't delete as says system app and no way to uninstall. Also checking app details says this is the latest version updated on 24/05/2018 so after doing reinstall still no change can't exit only way is to press home button and go to live tv or turn tv off and on.

@Rickles " Apparently one can add third-party apps to Samsung TV ... lots of instructions on the 'net after searching such "

None of these instructions will work