If you don't have a lot to ship back, it is worth considering sending it "unaccompanied baggage". I don't remember the exact cost but it was a fraction of the cost of sending it as freight.
You can clear it yourself very easily at the UK end but you should have the packing list and all your receipts handy.
We have followed this course twice and the second time the baggage was on the same flight as we were. You don't have to travel on the same airline either,