Thanks for that but I'll just try the one extra cable.
It's like a "snake pit" behind the TV already, as I've the Tivo box, the Humax, a CD/DVD player and a VHS player (I've a lot of vintage Film Noir on VHS) under there. The latter two have only scart connections so there's other stuff behind there to to convert these to USB, plus cables to my vintage Leak tuner amp and Goodmans speakers. So I can channel the audio from any of that lot through them.