Ok. Now I can confirm that iTunes Match does indeed actually stream.
Steps used to validate :
1. Opened settings>usage>music.
2. It showed 468Mb
3. Deleted the data. It then showed 0kb
4. Opened the Music app
5. Played one song by Dylan and the Dead
6. In theory this should have placed approx. 3Mb of data on my iPad
7. Closed the music app
8. Went into settings>usage>music
9. It showed 0kb of data.
Had this been a download it should have shown approx. 3Mb of data. It didn't. It showed 0Kb. so it did indeed stream.
Case Closed.

Steps used to validate :
1. Opened settings>usage>music.
2. It showed 468Mb
3. Deleted the data. It then showed 0kb
4. Opened the Music app
5. Played one song by Dylan and the Dead
6. In theory this should have placed approx. 3Mb of data on my iPad
7. Closed the music app
8. Went into settings>usage>music
9. It showed 0kb of data.
Had this been a download it should have shown approx. 3Mb of data. It didn't. It showed 0Kb. so it did indeed stream.
Case Closed.