I see discussions about cargo bikes on here reasonably frequently - often about how hard it is to find them secondhand - so I just thought I'd mention I've got one for sale in London - its an Urban Arrow Family - the top of the range one (so expensive even secondhand, sorry, but it is the most amazing bike, especially if you are somewhere hilly, it's basically a car replacement).
Shout if you're interested and I'll PM you the details. I really wanted one secondhand and couldn't find one because they come up so rarely, so it would be nice if I could help a fellow mumsnetter 
Regular poster but name changed for this as it potentially links to real life me.