Yes, the Audio Digital Mixer is more expensive for the mixing features, which I could use here in our school music dept. As a cheaper alternative to try first, I may option for as you suggest a stand-alone CD Writer that has Audio Inputs (not all of them have audio in I noticed the other day). Looking through Audio catalogues, CD recorders caught my attention. With a range of prices and features, could be a second consideration for getting my RISC OS !Sibelius files via the Roland Sound Canvas on to Audio CD.
Thanks for the tip.