Everything is here:
http://archive.imbenjam.in/musicofmerlin/media/
Note that the site is just pretty Apache directory listings, so no actual web site interface I'm afraid. Also, to save some time, you may notice that the structure is "park > area > ride/attraction", and every ride has a folder, but not every ride has files for it. You'll see for yourself xD
As I haven't worked on Music of Merlin in a few years, the files will definitely not be completely up to date in terms of the latest season, etc.
Oh, and if you end up taking any (feel free to do so), credit on your site would be lovely ;-)