Dear Jenny,
I'm sorry there seems to have been a problem regarding the price of your hat. The product page should automatically update the price to include VAT once you select an adult size from the drop down menu, then it's broken down again at the checkout to show how much of the cost is tax.
If it didn't show the update on the product page, please don't hesitate to contact us so we can look in to it.
Kind Regards,
Melissa
Ayr Equestrian