✔ 最佳答案
When you purchase goods over 50 pounds or 100 pounds, you should receive a VAT refund form. With the refund forms, you need to arrive the airport early and queue up at the VAT refund counter (At Heathrow Terminal 3, it is next to check in desk), At Terminal 4, it is after custom.
You need to show the staff the goods you have purchased in UK/Europe and they will calculate the VAT refunds for you. Note there is an admin charge and therefore you full cannot get full 17.5% tax back.
Hope this helps.
參考: Myself - past experience.