Before Christmas addedentry and I went to Velorution to look at their Christiania bikes. Sadly it turned out that I am too short to ride the standard models of Christiania bike/trike. :-( A follow-up email from Velorution revealed that there is a smaller-frame model available (7cm shorter, which we reckoned might be just small enough for me) but that they wouldn't be able to get it in for us to test (they could order it, but no way am I buying anything like that sight unseen). The Christianias look absolutely gorgeous, but if I can't physically ride them, there's no point considering them.
Velorution also let us try the TrioBike, another trike, which was just about small enough for me to ride it. The combination of tricycleness and handlebar-gearshift and Dutch brakes (ie backpedal to brake) made it feel Very Weird Indeed, and while I could imagine getting the hang of it eventually, I wasn't that thrilled at the idea: this wasn't meant to be a cycling challenge, it was meant to be a cycling solution. Also, the 'box' bit was really not a useful multi-purpose box like the Christiania's, it was a small plastic pod for a small person. This is all well and good, but part of the reason I wanted a cargo bike was as a general-purpose car substitute, for carrying Things as well as Child.
Plans to go to Cambridge still haven't quite turned into Actually Getting There, though we exchanged a few helpful emails with The School Run Centre, who confirmed that they have various bikes in stock which might be short enough for me to ride. However, while we were staying with addedentry's parents after Christmas, we managed to make a trip to Really Useful Bikes, who were incredibly friendly and helpful, and let us try a Bakfiets bike and a Gazelle Cabby. Both of these were a) small enough for my tiny legs, and b) surprisingly easy and pleasant to ride. addedentry strongly preferred the Cabby; I could have happily ridden either. By the end of a couple of short test rides I was confident enough to make a tight-ish turn at the end of the cul-de-sac without dismounting, and even went for a quick turn in the Cabby with baby in the 'box' -- she was much more cheerful at the prospect than she usually is in a buggy, and grinned cheerfully throughout our very short ride! The Cabby's box seemed a good compromise between designed-for-children and useful-for-other-things-too: it's made by the people who make Quinny buggies, and the seats/straps are like those in a buggy (and there's attachments for fitting a MaxiCosy car seat), but it's really spacious -- you could easily get three kids in there and some shopping.
So, the pros and cons of the Bakfiets and the Cabby:
* bigger box
* probably slightly more multi-purpose box
* more sturdy stand, possibly slightly easier to put up and down
* better-known make (though this probably wouldn't make much difference, except possibly for accessories?)
* nicer design
* Owen didn't like it as much!
* more expensive
* raincover doesn't collapse down, ie may be harder to carry around
* easy to fit a MaxiCosy car seat (though this is only really useful for tiny baby & we probably won't have another one of those!)
* 'box' folds up for easier storage and/or getting through side gate etc
* raincover is easier to fold (it's a bit like a tent, with collapsible poles)
* stand looks a bit more flimsy
* not as nice design IMHO
* less well-known make so possibly harder to get parts etc
* 'box' is canvas so may be harder to fix if it gets damaged (though admittedly this is probably not very likely!)
Basically there's not much in it, they're both really nice, and most of the 'cons' are a bit weak on both sides: I suspect the significant points are a) Owen's preference, and b) the price. We are still dithering, and would like to a) test-ride some more bikes if possible, b) test-ride the ones we liked again, and c) make a decision (which may yet include deciding not to buy any of them), ideally before March when Img will have to start at nursery and we'll have to come up with some reliable way of getting her from A to B (NB bus and foot are both plausible for the nursery we're currently most likely to go with).
Input welcome, particularly from people who have experience of riding cargo bikes and/or taking children on bikes.
PLEASE NOTE: if you comment to tell me that you think cycling is evil and dangerous and I shouldn't even consider taking an infant on a bike, I will delete your comment, and may block you from further comments. I'm not interested in rehashing that particular argument; I have considered the risks and come to the conclusion that they're acceptable in return for the benefits. There is no such thing as a risk-free activity. Please respect my right as an adult to make my own risk assessments within the limits of the law. Your statutory rights are not affected.