I believe it was split runs, as described in Charlie’s post above. Lee Valley has a 140m straight and a 200m indoor track anyway. It’s a great facility, and I wish I lived or worked as close to it as you do. I used to drive 45min to the Brunel indoor track up to twice a week and sometimes even took the 1:30h drive to Lee Valley for training purposes. I would expect the roads to be clear there.