Agree I think Joe is using this new channel to show off his girl, he never had before & he wants to show her off & the way he knows how to do that is through YouTube.
One of the reasons he probably didn't want to use Thatcher Joe is because that is for his pranks, challenges etc and he probably didn't want to take the piss out of Dianne, or prank her, which is what the people who still watch his videos expect. Yeah in the pan will still have his childish sense of humour, but won't be completely off the wall like Thatcher Joe.