I've since had confirmed from iTunes Store Support that-
"The answer to you question is, Yes. The music that you did not purchase form the iTunes Store will automatically be available to your devices as long as it matches with the songs available from the store. For you to understand better, I provided some articles that will confirm my answer.
If you want the benefits of iTunes in the Cloud for music you haven’t purchased from iTunes, iTunes Match is the perfect solution. It’s built right into the iTunes app on your Mac or PC and the Music app on your iOS devices. And it lets you store your entire collection, including music you’ve imported from CDs or purchased somewhere other than iTunes. For just $24.99 a year."
On the strength of that I am willing to give iTunes Match a try, I guess.