They don’t need radar or laser equipment, but it does need to be calibrated if that is what they are using for the basis of the prosecution.
A traffic officers observation is sufficient to get a conviction in a lot of cases. They don’t even need to specify the speed, ‘no less than X mph for Y distance is sufficient usually, they know that because they are usually following you. They also use video evidence from onboard cameras regularly. If they don’t go for speeding, due care is a catch all basically and has the same outcome.
A whiteness statement and video evidence from the general public can be used for due car or dangerous driving without issues usually. The difference in outcome is minimal in reality compared to speeding.
It’s obvious from the earlier video the person was traveling at excessive speeds, add in the wet conditions then charging with dangerous driving isn’t that far fetched. Whether they drop it to die care later is another question.
You can get a ball park from the number of lines both cars pass on the roads for a given number of frames. No they are not calibrated but they are a known quantity and close enough to determine it’s significantly over 70mph. The whiteness statement is to validate the video hasn’t been tampered with, that’s all.