I have sent numerous items to my family in the UK, Australia and New Zealand. They have never had to pay duty or VAT. First of all, don't wrap it up as a present! They'll just unwrap it! You will have to put a value on it, so put the value of the materials used in the quilt on it. Then emphasize that this is a gift. For instance, I will write on the Customs form: Gift for sister Linda for birthday. Then I will put the same information, along with her address, and pin it to the quilt, in case they open the box and the custom's form gets separated. Don't send it air mail. I've sent it the cheaper "overland" many, many times, and it never takes as long to get there as they say it will. For a quilt, I would seal it in a plastic bag, and put the extra set of information in a plastic bag and tape it to the outside of the plastic bag. I've had things get wet in transit, which makes sense if they're in a container on a boat. Even on a boat, it didn't take 6 weeks to arrive!
Good luck to you!