Hello Daniela! You can see, quiltfriends are everywhere!
Of course it's always kind of a risk to send a quilt by mail overseas. When it should get lost you can never replace it. I sent quilts by DHL several times to UK and NL and everything was perfect. The quilts arrived in time, no damages at all. Grosvenor is sending an email with different transportation offers and of course for different rates before they send back the quilt and they really handle everything with care. All my quilts arrived home safely just a short time after the show. The Grosvenor staff is very friendly and you can ask questions by phone or mail all the time.
Just give it a try!