Hey Neil, The overall form is great ... It looks nicely designed and i particularly like the 5 order option windows.
Now, I'm not trying to be a smart arse here, but you asked for comments ...
I trust you spotted the typo - "5 casts each, to give oters a chance. "
and I think the following reds a little clumsily:
A PAYPAL invoice will be sent to your e mail address so that you can pay for this order that you are about to place to the UK cmp.
Maybe reads better as:
A PAYPAL invoice will be sent to your email address. Please follow the PayPal instructions to complete your order.
And finally, If the form was mine I would drop the asterisks adjacent the "order line" windows and put one at the bottom with the following:
* indicates required fields.
Simply because if I see an asterisk on a form I have to go see what the clause is.