I hope I'm not doing a grandmother sucking eggs thing here!
I'm in the process of selling a fuel tank from a CF through the Bedford CF club,the recipient lives in Jersey.The tank itself only weighs11kgs & measures 95cm x 62cm x 30cm.Because of its size they process it by its volumetric weight which then adds about another £6 to the cost.
So,if you have bulky items to send,don't just price up by its weight.