Transporting boxes from London to Cannes

If the boxes are larger than can be handled by the postal service, www.shiply.com is a transport marketplace that matches transport providers with customer requirements. I've not used them but have heard good reports; final service will depend on the actual transporter selected and quotes can vary hugely.
Unfortunately their website is down at the moment, probably not for long.
Steve

I have used http://www.loadup.co.uk to get stuff from Marbella to France. For part loads it works for both parties.

There are lots of white van man types toing and froing across Europe. Best if you can wait for the right one to come along.