Visited this garden (and indeed Cambridge) for the first time this week and was very impressed. A beautifully kept garden with a huge variety of plants. If you get a chance, do go- it's on the Trumpington Park and Ride route into the town centre which is the only one that has camper van spaces, if anyone's interested!
http://www.botanic.cam.ac.uk/Botanic/Home.aspx (http://www.botanic.cam.ac.uk/Botanic/Home.aspx)
I visited these gardens with Georgie last year, hoping to visit again this month. I also did the park and ride journey. Well worth a visit.