I have found the less I say, the better. When using call letters: If I say, "play station KNKX" it plays that tunein (or iHeart ) station. For stations that call letters do not work, I say, "play station Jazz Wyoming" it works. (Yes, there really is a good jazz station in Wyoming!)
Key words to always say are play, station, and of course, station name. Try this format with your BBC stations.