>>>Some people would ask the seller to tick the 'gift' box on the Customs declaration but I am not sure if its 'Legal' nor what law you would be breaking or who would be prosecuted
To qualify as a 'gift', the value of the item must be less than £36. It must be sent from, and, to, a private individual. There must have been no payment made for the item, directly or indirectly, by any person within the UK. The gift must be of an 'occasional' nature only, such as for a birthday or Christmas present. A CN22 customs declaration form must be correctly completed.
Any item received without a CN22 declaration, or one that declares an item to be a gift when it clearly isn't, is liable to be seized and the person commissioning the import (e.g. by ordering it from abroad) can be prosecuted using anti-smuggling legislation.