Yes I think it's only been since 100 Days began that the News Channel has taken the same programme also.
Yes, historically News 24 always did its own thing at 7pm.
When BBC4 started up in 2002, BBC World produced a specially branded bulletin focusing on international news and analysis, which was actually very good. Curiously, the programme was branded differently on each channel - it was "BBC World News" on BBC World and "BBC Four News" on BBC4. Somehow they managed to play out two versions of the titles simultaneously, although I've never been able to figure out how! Unless BBC World Pres had something to do with it? I think N9
used to play out the BBC4 branded version.
That rings a vague bell - I think World Pres
play out separate titles for a time ...
It was only the very opening sting that had separate branding - the titles after the headlines said simple "BBC" (probably why those unusued titles went unused). So it seems likely that BBC World pres played their own sting and then went to the studio for the rest of the show which is a lot easier than jumping in for the main titles and then back out again.