Quote: The Video Ref "Anyone who tries to overtake you whilst you are in the process of lawfully turning right will be liable for the collision, assuming you have properly indicated your intention to turn right. '"
Absolute nonsense, I'm afraid. You astonishingly state that as long as you indicate, this absolves you from any responsibility, but that is wholly wrong. .
Your use of the word "lawfully" doesn't add anything, and only serves to confuse the issue.
However, and whilst the Highway Code is not "the law", it can be pointed to (and very often is) in support of allegations of negligence, as in, we are all supposed to know it, and comply with it.
On this specific question (with the most relevant bits highlighted) it clearly statesT
urning right
179 Well before you turn right you should
* use your mirrors to
make sure you know the position and movement of traffic behind you
...
180 Wait until there is a safe gap between you and any oncoming vehicle.
Watch out for cyclists,
motorcyclists, pedestrians and other road users.
Check your mirrors and blind spot again to make sure you are not being overtaken, then make the turn.'"