Well, as someone who has actually shipped a number of knives, I can tell you my experience. Listing the contents as "camping tools" and "gift" is quite common. Having the word "knife" on a package is a sure fire way to have it opened at Her Majesty's Customs main clearing facililty, which is affectionately known to the locals as Mt. Doom.
As for legality, short of specifically prohibited items like automatics, disguised knives like belt knives, etc, "kung fu weapons" like shurikens and "knuckle duster" knives like the WW1 trench knives, it is not illegal to own most knives in the UK. The crime is in carrying anything other than a sub 3 inch slipjoint. The othe thing that you cannot own is a curved sword over a certain length, but after much fighting by bladesmiths, there is an exception for swords made "by hand in the traditional manner" The purpose of this law was to ban the trade in cheap knock off katanas, which, by the sensationalized press accounts which the UK is well known for, were being used left and right by marauding bands of liquored up Chavs to slaughter everyone in sight.
As for ivory, the only kind of legal elephant ivory in the UK is stuff that is over 100 years old and has not been altered from it s original state. George Trumper, a very old and established Curzon Street barber shop and mens grooming store, was fined something like 20,000 pounds a couple for years back for merely restoring and revamping some antique ivory handled shaving gear.