over $1300 import duty to UK
I don't think it's quite as bad as that:
Import duty is I think 14%, plus shipping, plus 20% VAT, plus the handling fee from the courier. Bike parts are cheaper, I think 4%, so breaking it down into two lots might save a bit.
Still means it's not worth it, but a long way short of $1300
It's a bit of an oddity, that's a pretty old hub, when did they stop having the stickers on? Did Thorn really have a new one of that age to sell last year?