AB doesn't ship to the UK - I'm sure you'll notice a lack of UK transhippers, but alot of people use a UK oriented website for bettas.. I'm not sure of the name though - I'm sure someone will pop in with a response.
you can ship fish off aquabid to the uk,Kgbettas letsyou do it through him,If you do get fish off aquabid then i would suggest getting like 8 fish to make up for postage,