I have just found out about this website.
http://www.collectplus.co.uk/
It is a service in the uk that lets you send items to local shops rather than to an address. I have always wanted to do some gear swapping, but have never wanted to give out my address. This website lets you send your package to a local shop near the person you are sending to so you never need to give out either address. Simply drop off at your local shop then have the recipient collect at their local store, its brilliant!