Ok, Will probably sampled from Papua New Guinea from The Future Sound of London, which sampled from Dead Can Dance's Dawn of the Iconoclast.
You'll hear it clearly here:
"Papua New Guinea" by The Future Sound of London contains a sample of another track. Listen to both tracks on WhoSampled, the ultimate database of sampled music, cover songs and remixes.
www.whosampled.com
(there is no entry for The Last Rave on Earth yet)
Then compare with the sample of Will's track at 2:28.
Dead Can Dance's female vocalist is Lisa Gerrard.