Your method of calculation on the images is wrong. You're lining up the numberplate at the back with a road line that's beyond the front of the car.
To me it looks like her rear wheel is half way between 4 and 5 in the first pic and past 9 on the second.
That's pretty much 5 lines = 35mph.
its the clearest part to compare, as long as he uses the number plate in both pictures then it is ok to use that to count how many lines were crossed.