cbbc's birthday

Wouldn't have thought so - they probably did before CITV was established as a strand, when the regional "Watch It" was around in the early 80's.

Were the programmes shown at the right times? It wasn't a timeshifting arrangement perhaps?

Or some sort of bizarre network fault where they couldn't get a feed from Central but could get the programmes (which were all played out by the individual companies that produced them), and anything made by Central would have been replaced by something played in locally? Although I guess in that situation a bit of overplugging at BT's end could have sorted it.

On knightmare.com there's what appears to be a Thames regional opt-out from 1992. Phillip Elsmore introduces Cartoon Time over the CITV ident.

Has to be either an opt-out or the ident's been cobbled together from a previous playout and had a final frame hold tacked onto it (notice the cue dot on the clip in question).

This would have been on a Friday afternoon when Thames used to use a filler to take it up to the 5.15pm handover to LWT. As you indicated, it wasn't an "official" CITV junction.

Normally Home and Away would run from 5.10pm - 5.40pm at that time, the two stations would switch-over during the first segment. But when H&A was not showing, they filled up till 5.15pm when LWT would take over.

I remember Tyne Tees doing this on one occasion as well, and that was in the Summer of 1983. Bill Steel popped up after the ads with birthday greetings then they opted straight into the next programme's opening titles (which I think included Runaround). Bizarre!