I also experimented with taking a video. The mobile phone is in the clear plastic part of the handle bar bag.
I have downloaded the Prune program to draw my map. It shows the route and the altitude which is cool for a GNU free program. The ride is from right to left on the map, but left to right on the altitude.
16.4 kmh is a bit abysmal and I struggled on the hills to keep up. In fact I was dropped from the pack on every hill. But I caught up again. Still, once I am going well I should be able to manage 25 kmh on average.
Now I need to do the ride to work and back to show the map, also into 400G in the city.