From their announcement:
We’ve had gremlins in our web site! We know that some customers have unfortunately been unable to place orders. We’re so sorry if that was you and we have worked with everyone concerned to eliminate the gremlins.
Because of the this, we are extending our half price offer on the New Uncharted Seas Rulebook. You now have until 8th October to spend £60 in our online shop and buy the rulebook for half price. Add Coupon USRBHP on the Checkout Confirmation and the shop will automatically give you 50% discount on any Uncharted Seas Rulebooks that are on your order.