[Keith]

Great thread on how they switch from BBC National News to BBC London
twitter.com 

This was linked to on the previous page in pres.cafe .

Worth noting that the twitter thread has been updated to included what happens when Huw walks.
twitter.com 
I'm guessing that with the 'walking' camera being automated and relying on the presenter keeping pace may be a factor in why most presenters no longer do this. Additionally, it's looks like it's a lot tighter for the London presenter to get into position, though it may help that the Ten can first show a shot of Newsnight starting before the nation/region screens.