At about 1m40 it says "erratic policy is hampering Britain's already ailing manufacturing industries" which doesn't really seem to be backed up. Especially since the UK overtook France this week to become the 8th largest manufacturer in the world.
The economy is on its arse for sure but this piece seemed to want to tell a specific story regardless of the nuances/facts.
E: if you read through the comment section on YouTube there are loads of other issues/inaccuracies being called out
Quanta is just a word (related to quantity) as in: "smallest divisible quantity of"
So in the case of light we would be talking about photons, which are a quanta of light (e.g. discrete "packets" of light).
Light behaves as a wave, e.g. we can talk about the frequency of light. But it's also pretty different from macroscopic waves e.g. it's not accurate to think of them as what your see on a typical sinusoid graph, as at that level things don't really have a fixed shape or position, we're talking more about areas where they "probably" are (see: superposition, HUP etc)
It's useful to think of light in terms of discrete photons for a number of reasons, e.g. in pair production, 1 gamma photon would be sufficient to create 1 electron/positron pair.
Photons also exhibit other particle-like behaviour despite having no rest mass. But the idea of rest mass becomes less significant at that level anyway as the line between energy and mass (e=mc²) gets blurred. And any sufficiently high energy object will likely exhibit some massive properties (hence why we tend to use MeV - a measure of energy - instead of a measure of mass, even when performing calculations with massive particles such as electrons.