Box shipping to South Africa

I am heading to Cape Town, South Africa to do some field work for a year and need help with some shipments. I am going to be leaving most of my things in storage here in London while I am away, being that it is only a year I will be down there, but I still need to ship some of my things. I have about a dozen boxes that I intend to ship from London to Cape Town, none of which are too terribly heavy. I have packed my books, clothes, photo albums and other personal items in them. All of the boxes are either 3' by 3' or smaller and weigh less than 10 lbs each if that helps. I can break them down into smaller boxes if you think that would make a difference in the price to ship them down there. I will be carrying my laptop and other items of value with my on the plane so that I don't have to worry about them being lost or damaged in transit.