I do get the impression that the London leg was expanded from 1 to 2, and things might have been hectic production wise. Things were already getting pretty bad in some countries. They probably might have done a single daytime leg, instead of having a short night leg with another daytime leg. All we can do is speculate.
The lack of a starting line, was probably to give Phil and team a proper head-start time in the UK, which might have included all these leg adjustments. This was mid-Feb20, it would be another few weeks for the WHO to declare it a pandemic, however COVID cases were already soaring in certain parts of the world. Teams were probably in sequester and production chose to return them all to their hometowns, for this remote TAR28 style race start.
Back then, I had a huge work event planned for March 2020, and I remember being super hopeful we would be able to make it happen, before things got worse. We ended up cancelling it a few days before, around the time the WHO declared the whole thing a pandemic. It might be myself overthinking things, but the TAR Production was really hoping to be able to wrap the 20'ish days that usually takes to film the race, before things got worse, and things really did not pan out.
