My mind has gone there already CC!
Well there would be duties, but I would be able to use my duty free threshold (and DD's) which you only get access to for goods carried through customs (not for stuff mailed) and then I'd only have to pay duty on the remainder! Be still my heart!
Actually the website says if you exceed the threshold you have to pay duty on the lot, but I've never seen that happen if you are honest and tell them everything you have.