Putting an item marked as a gift wont mean you will get it minus vat from different countries. I think we have all used that one and still got done. If I worked at customs and I seen the thousands of items coming into the country marked as gifts, I would certainly open them just to see if they were. I think they have cottoned on to the gift thing by now.
I would pay it and put it down to experience rather than mess about. Next time they may open the product, think its worth more than the parcel says, and whack even more vat on.
My 2p's worth
Nige