The United Kingdom (UK) is a customs country with rules for importing and exporting products and there are costs involved. More information you will find on dpd.nl.

Import costs:

Import costs consist of import duties and VAT. All goods under £ 135 are subject to VAT. Goods over £ 135 are subject to both VAT and import duties. 

The amount of the import duties depends on the value of the parcel and the products you send. Valuation is done by customs. They use the HS code of the product you are sending. DPD has no insight into this.