I have now taken out a Premium Plus membership with Jazz Groove for one year. I now have access to 5 separate jazz radio streams without adverts or interruptions in FLAC quality (44.1 kHz). The integration into the Naim app worked as described in the instructions on the Jazzgroove homepage. It’s a bit archaic because in the Naim app the stations have to be added manually on the VTuner website. Also, station URL’s have to be copied and pasted from the Jazzgroove website. In the end, however, it worked and the 5 Jazzgroove streams can be started in the Naim app (Webradio - added stations or defined as presets from there). They also offer metadata of the current tracks. I have not found the LOGO URL of Jazzgroove, so that no Jazzgroove logo is displayed in the Naimapp for the 5 streams. The skip function is also not available in the Naim app. But these are minor issues, the streams work and offer great sound quality (even higher than the already good MP3 quality of Jazzgroove West/East). A good thing for regular users with audiophile demands - recommended.