[DTV]

One thing I don't quite get is this: the 5pm GMT hour is presented by (and AIUI also produced by) the same people who do the One. World goes separate for the 1pm hour in Studio C. Is there any particular reason why the One team couldn't simply stay on until, say, 4pm (as they did during the first lockdown) for a couple more hours of UK-only news? I know similar solutions were suggested multiple times in the run up to this merger, and it would seem to me to make much more sense than what is currently done.

Absolutely, it would be eminently sensible and would not be the only way of squeezing out a bit more UK-only output using domestic teams. While, yes we have to see what the UK-opt and wider finished product is like in practice first, the fact that (fairly obvious) compromise solutions like that were avoided - even for the interim period - does have a real 'cutting off your nose to spite your face' vibe to it.