Based upon a purchase price of �60, here's how the sums add up:
Duty is charged at 12% of the purchase price. 12% of �60 = �7.20. (NB: You might not have to pay duty. See below for an explanation).
VAT is calculated as 17.5% of the 'value' of the boots, where 'value' = cost price + duty. (Yes, that does mean that you pay VAT on the duty!). 17.5% of �67.20 = �11.76
Then there's a flat fee of �8 for the examination of your package by Customs.
That means that the postman would demand payment of �26.96 before handing over your parcel.
However, things might not be quite as bad as that. Duty is waived if the amount comes to less than �7. So, if the cost of the boots was, say, �58, the nominal duty would be �6.96 and this would be waived. (The sender has to declare the the price of the goods on a sticker attached to the package. Whether you'd have to pay duty would depend upon the exact price stated and the rate of exchange used by Customs for converting the price to sterling).
If the price was �58, you'd still have to pay �10.15 VAT, plus the �8 examination fee, so the postman would require �18.15 from you.
In general, it rarely pays to buy goods from non-EU countries unless they're either free of duty & VAT (e.g. books) or the price of the goods is less than �18. (VAT is waived in this case. The examination fee is also waived when there's no duty or VAT to pay).
To summarise, if the purchase price is just below the threshold for paying duty, the postman will demand around �18. If you have to pay duty, he'll require about �27.
Chris