Thing is, if you're talking about releasing something that's not seen the light of day anywhere else, you're guaranteed to sell a shitload through the likes of Amazon. While you only licence titles for the UK, there's nothing stopping Amazon selling your product on their .com, .de or .fr sites, and there's enough people worldwide who'd make such a move lucrative...
There's an example--and you can ask Neil from Pink about this--an Artificial eye title was predicted to sell around 300 copies all told. Still not too sure why it was getting a release with those kind of numbers in mind. anyway, a couple of weeks before release, World Cinema were given a 250+ order from amazon alone, as they'd sold a shitload of them through the .com site. this is definitely something worth keeping in mind.