Thanks so much for all your help, stretch and EVILRipper. I now understand the instructions given in the link and have followed them exactly. However, it makes no difference; i.e., there is no change from the before situation – nothing appears in the Music part of the Library section of iTunes, but the whole of my music collection still happily appears in the Tunes Server of the Shared section of iTunes. It’s just as though all those steps are an intricate way of giving me what I already have got through standard iTunes functionality. That is, play access to my music library on the NV+ Firefly streamer, but no sync or playlist functionality whatsoever.
Isn’t life frustrating at times?! 😕