I've had similar experiences, last one was some t-shirts from America. About half the cost of the shirts in taxes. There's VAT, import duty and the Royal Mail charge which I believe is a set rate of £13.50 or £8.50 IIRC....Some bullshit like that anyway.
Used to be able to get round it by marking it as a gift, though that tends not to be an option any more at least in my recent experience
