I'm not sure an isolated score track is plausible. There are a myriad of sources for Vangelis' score, but unfortunately they're all problematic.

The original soundtrack album released in '94 contains only selections of the score interspersed with new material (“Blush Response,” “Damask Rose,” “Rachel's Song,” etc.), has segments of dialogue over it, a lot of additional reverb added, and several of the tracks have been remixed or altered, such as the original synth saxophone in the “Love Theme” replaced with an acoustic performance.

There was a three-disc set that came out a few years ago, disc one was the original soundtrack album, disc two was additional music from the film, also with the additional reverb, remixing and new performances.

Bootlegs exist, and are much more satisfying in terms of representing the music as it appears in the film than Vangelis' own concept albums, but all of the ones that I've heard have had serious sound quality issues.