It'll depend on how the customs declaration is filled out by the sender. I seem to remember that 'gift' or 'work related' isn't looked at by HMRC but 'goods' or 'purchases' are.
It's a lottert and you've got to remember that goods bought abroad should be taxed so be happy with the ones that weren't and put up with teh ones that are - or make sure sender know what the right on teh ticket
Andy