Ouch, yes, that is insane. There must be other ways (which is not to say they're necessarily practical in this case...) -- e.g., i can buy (and have bought) US-stocked second-hand books from BetterWorldBooks for under $4, *including* shipping to UK (which is equally insane, but in a better way)!
Maybe try to distribute through amazon uk? I know for sure that they do market privately published books (from outside UK), at inclusive prices again typically less than your quoted shipping costs.