Another freight option is Parcel Broker -
www.parcelbroker.co.uk/smcka They are pretty good with rates - about $80 for 6Kg dead weight.
I use them for all my freight, even from my main suppliers as they stick you with freight.
Basically you ask them to give you the weight and dimensions, you book it, pay for it and then email the con note to your supplier to stick on the box.
Simple, easy and cheap. Book it in on Thursday UK time and you'll have it normally by Monday as it travels over the weekend. It is actually DHL and you can track it live on DHL site.