Having started this at 7:45 I thought it best not to cycle back along the river as I suspected it would be busy with boaties – though a change of scenery is always good anyway – so I instead came back through Horningsea and Fen Ditton. This altered route came to 37.52km – which is pretty much the same as the normal one, if anything slightly further. My average moving speed was 27.16km/h – which is (just) a new personal best for the semi orbital routes (previous best 27.15km/h on the normal route).

Route:

View Cambridge Semi Orbital Variant 1 in a larger map

Here is the Google Doc with all the stats:
http://spreadsheets.google.com/ccc?
key=0At0EKwdiLZmYdFg4Mk9fdHltdWlGeWpQTHMzM3RjU3c&hl=en_GB