Thanks for finding that other youtube video. That is exactly what I was referring to (you are right), and I did NOT know where the source of those video clips, originally came from.
Finding that second video, has been a massive help to me!
But, now I know. As you said, the credits (spoiler alert: Do NOT seem to mention BigCliveDotComs real life name), and he does look a bit (or more), different to Clive.
Because he seems to have his head pointed to his left hand side, I wondered if he was hiding the single ring, that Clive seems to always wear in his ear.
tl;dr/Summary
I agree with you, I seem to be wrong, and it is NOT BigClive.
In my defence, BigClive most often, doesn't appear on camera in his videos, and the video was taken some time ago, hence showing a (date was not obvious, from original video source) much younger BigClive.