Thank you, Alwyn (and thank you for the brevet card which arrived yesterday).
If one downloads this worksheet, sorts it by London Depart (Col A oldest to newest) and then by St Ives North Arrive (Col B oldest to newest), since one knows these two data one can identify one's personal line swiftly.
For those of us too slow to take the tracking data off the live site on the Friday before Phil closed it (I was still in Loughton clearing up, till after the Chinese Takeaway), we now have the checking out times at all controls where the rider made the effort so to do.
Much more fun to be had, of course.