Start at the northern edge of rectangular manhole, which is at the northern end of the Willoughby Bus Stop Lay By.
Proceed northwards on the A45 to the Dunchurch M45 motorway exit roundabout, where turn and retrace on the A45 to. Finish at mark on the kerbside just after the 2nd canal bridge at Braunston.

(This is the K11/10B finish point)
(Distance between the start and the finish is 1.32 miles.)