The idea is to "Find it. Rip it. Mix it. Share it. Come and get it." Unfortunately, people outside the UK won't be able to get it. The archive is "funded with public money to serve the UK population."
Still, in an era of bittorent, it seems having a mirror at archive.org would make sense. I'm sure people would be willing to donate a few quid (or euros).
Update: so far, the BFI videos can be viewed in the US.