Thanks for all the comments! At the weekend I'll try to find time to make up some kind of journal website with more photos and detail about the trip, and I'll post the URL here.

Scruffychimp: you're right - there aren't many hills to choose from in Cambridge. You can either do laps on Castle Hill, or take the bike on a roof-rack to North Wales! In fact I think I did most of my 'training' on an old Roman Road which runs from near Addenbrookes Hospital to Haverhill - rough, off-road track with some slight undulations. If you haven't found it yet, it's a good way to spend a couple of hours on a sunny day.