And I dont know in the UK, but in Spain if you receive the parcel by normal post (Royal Mail for your country), most times they ask for invoices of the items to see the real value; they want the value justified. But if you receive the parcels by courier (FEDEX, UPS, DHL, etc.), these companies won't ask you for any invoice and will charge you only for the value which is declared on the package attached invoice. Without asking if this is real, or it is not.