Eurostar site not a star

On first viewing the Eurostar website you think - "this is pretty convenient... all the train times and ticket details are available and easily searchable - we'll save some time by using this site instead of going to the travel agent." You get all excited because the deals are cheaper than the travel agent quoted and it's really a matter of choosing the right train time (Kath: "should we arrive 6 or 7 to avoid peak hour traffic... or later maybe... but that's too late...").

But then you get to payment and things ALL go wrong.
The postcode box was the first little hint things were going wrong (when will websites learn that Hong Kong doesn't have postcodes, so what do HKers fill out in these mandatory fields?).
But then you get to payment and things all go wrong... You put in your credit card details and then it says transaction cancelled and then you lose all the details you just entered, plus the prices on the website all change from US$ to Pounds, and they are all twice the price, and I can't get back to the deals they first quoted us. All of a sudden we are looking at GBP200 instead of USD180!
I really hope they don't charge Kath's credit card too, as we did go through the whole booking procedure and it failed right at the end. Now I can't get it back in US dollars too. Frustrated.