2. "All that slowing down does is delays your getting to the back of the next traffic queue."
I understood that to mean that there is no point speeding as It will not improve your journey time
Every time in central London where there has been a noticeably identifiable car - usually one with loud music coming out, lots of customisation on the outside and an aggressive driving style - I have made faster progress than them. It usually involves them doing an aggressive overtake and speeding off and then me catching them up and pootling past them at the next traffic queue. This is repeated multiple times with them getting further and further back each time. Eventually all you hear is their stereo fading into the distance behind if they haven't turned off.
And to date I have never been beaten to the next meeting or back to the station by colleagues taking a taxi or the tube so it seems more generally true. Even Top Gear's race from Kew to City Airport was won by the cyclist by a big margin. Even public transport was faster than the car.