Livre d'Or

Haven't read other comments, pldase forgive repetition:

Mudguards and a skirt guard keep clothes clean and stop long skirts getting caught in your wheel.

A fully-enclosed chain stops clothes getting caught in the chain and also means the chain needs much less maintrnance. It also means you need to have hub gears (if you have gears at all). You may not want gears in Cambridge but if you do I think 3 should suffice. They're quite helpful on hills or in a strong headwind.

I like having a front hub dynamo which runs a very bright front and back light. This is expensive but means I am never caught without batteries in my lights. (I use battery lights also, partly because belt-and-braces, partly for better total visibility).

I wear a helmet that looks like a hat. This means I don't suffer as much from the "she has a helmet, I can pass v close" problem, but if I get squished by a lorry nobody will tell my grieving family I should have worn a helmet. Bandbox and Yakkay are two brands that sell helmets with various different covers. Neither are cheap.

I have never fallen off my Dutch bike and accept that in injury terms the helmet is probably extraneous.

For a "just get on and go" bicycle I think it's hard to do better than an upright Dutch-style bike. They are not light and therefore not very fast, but they're pretty reliable, and with the right panniers can carry a week's worth of shopping. Thry'd be fine for things like a day trip out to Wicken Fen for a picnic, too.

Your bike needs to be harder to steal than the other bikes. Using two kinds of lock helps.