The way the music tracks have been put on the DVD is rather confusing. Basically they are on two of the episodes (I think for memory the other one is 3, or 5??), but there is no logic to viewing them with the episodes - they've just been put there because there was a spare audio track they could use. In neither case does the music track last for the full episode length.
The easiest way to listen to the music properly is to use a software program to strip the music tracks off the DVD and save it as a music file/CD so you can listen to it on your hifi. I found 'DVD Audio Extractor' - which has a 30 day free trial and with that you can make a CD of the music from both episodes (make sure you select to insert tracks, otherwise you'll end out with 2 twenty minute tracks which are hard to navigate.)
Sadly the music is only mono, and not really CD quality, but it's still nice to listen to on its own.