price of the item.
HMC&E perfectly capable and willing to call out false declarations of value and hold an item until the recipient is asked to prove what they actually paid. not happened to me, have read of it.
they don't have to believe the idea of a declaration as a gift either, if (for example) it's from a business sender rather than an individual.
they're using their own predetermined exchange rates for each calendar month, so don't bank on saying the rate made my item under £15 on the day i ordered it :
https://www.gov.uk/government/public...r-2018-monthly