Customs is a hit and miss affair.

I order a lot of DVDs from America and sometimes I get customs thrown on top most of the time I don't.

It was particularly annoying with my Val Lewton box set because I waited a long time for the thing to arrive and when it did I got a slip pushed through the door instead of a delivery, demanding more money than the cost of the set in customs (they set the customs charge on the retail price rather than the sale price).

I've just ordered a number of DVD's for a project I'm working on and I'm dreading the gray slips again (maybe I will get lucky this time).

Customs on declared gifts are daft especially when the item is second hand, it make you wonder where they pull these values out from.

HM Revenue & Customs said:

2.4 Gifts

Goods sent as a gift that are over £40 in value are liable to import VAT. Customs duty also becomes payable if the value of the goods is over £135 but is waived if the amount of duty calculated is less than £9.

To qualify as a gift:
the customs declaration must be completed correctly
the gift must be sent from a private person outside the EU to a private person(s) in this country
there is no commercial or trade element and the gift has not been paid for either directly or indirectly
the gift is of an occasional nature only, for example, for a birthday or anniversary.

Note: if you purchase goods from outside the EU to give as a gift to a relative or friend, whether or not addressed to that person, is treated as a ‘commercial consignment’ for which the import VAT relief threshold is £18 (paragraph 2.3 refers).