YouTube puzzle

Today I had an email from someone who could not access a YouTube video of mine referenced in my recent RSGB RadCom article. When I first tried it said "video unavailable". I tried again typing the link in the article and all was fine. It said the video had had 240 views.

The person tried 3 times again without success. So I tried again, this time as my wife with her ID on her iPad, typing in the precise link in the RadCom article. No problems except it now said 2416 views!

So, I am totally baffled why the views seem to differ so much and why there should be access issues. By the way, I checked the video was definitely "public" and not "private" or "unlisted". All very odd.