I've learnt the hard way.. I posted a bracelet to my niece for her birthday and because the value was over £40, she had to pay £18 customs charge before the post office would release the parcel.. It was only worth about £50!!!
I order all my gifts directly from uk sites now & get them posted directly to my family. Amazon are always good.. Boots, m&s etc..
. I also kept a uk account for payments to keep it simple.