When i was buying and selling car bits a few years ago i used to use a company called Gefco, They were the cheapest around and would ship anything worldwide. They were especially cheap for Europe stuff. One i remember was 3 boxes weighing in at 30kg's from Manchester to London cost me £15+Vat.
They ship on weight not size so a frame i would imagine will be quite cheap to send.
Another thing i remember was it was sometimes cheaper to arrange the collection from the other side. In this case it may be cheaper to get Gefco Germany to collect it and ship over via Gefco UK.