Thanks, C_A! I was beginning to suspect that I had it tagged to the wrong episode - didn't think it was S5 though as I was thinking that that plotline had been resolved in the S5 opener, rather than continuing on. I'd begun to think it was the penultimate S4 episode, rather than the finale.
Still not ringing any bells, mind you.
But, at least, I now have the name to be going on with.
And thanks for trying, Paul - in spite of my confusing the issue.
Hmmmmmm. A quick look at Wiki says it's been used on several 'Academy nominated movies' - but doesn't list them, helpfully. So it's possible that's where I've heard it before. Other than that, the only usage that jumps out at me is Andrew Marr's History of Britain. That was a series Stuart and I religiously watched each week, so it's possible that's been where it's stuck in my head.
ETA: Just realised that Lisa Gerrard was also responsible (with a co-author) for Now We Are Free, from the finale of Gladiator. Another beautiful piece that I adore. Which may explain why I kept thinking that I'd heard this in Gladiator, then dismissing that idea with I was mixing it up with NWAF.
LabRat