@Disloyal , I wouldn’t recommend looking for a second hand bike when your DD arrives in Cambridge if there’s any chance of bringing one with you. That’s what many other students will be trying to do. They are probably less expensive at home, too.
(There may be schemes in certain colleges where you can to buy bikes left by graduated students, but I don’t know about that. Presumably colleges will advertise that in advance to their first years.)
Unfortunately there is a lot of bike theft in Cambridge, and you don’t want to inadvertently be buying a stolen one.
There’s a private group on Facebook called Official Stolen Bikes in Cambridge which aims to reunite bikes with their original owners and draw attention to the thieves. There are other FB groups, too, and the number of reported incidents can make theft seem inevitable.
However, my neighbour works with the police in a field related to bike theft. She tells me that levels of bike theft in Cambridge are not increasing, (but doesn’t deny that they are high) and that it’s a good idea to register your bike (and other valuables) with Immobilise . It’s free.
There’s also the Bike Register. There will probably be free sessions in Cambridge to get signed up for that.
It’s often said that the oldest, tattiest bikes don’t get stolen, but they do. Making your bike distinctive can help, as can using two locks of different types.
Colleges often have places where students’ bikes can be locked away together, especially over the long summer break.