Were LWT local trailers made by the Leeds team during this era or still made locally? If it’s the former, what style of endboard did they use, one matching the network trailers?
The timetables of the development of the hearts and the YTV local ident is a mystery to me, it’s interesting that on one hand we are told the ident was supposed to be for all junctions (hence why they made a million versions) but then on the other hand the background of this ident was so similar to the hearts background as if they were meant to compliment each other.
Also that they’d already made Christmas versions for everyone, but hadn’t made normal versions for everyone. All quite odd.
Not sure about LWT trailers. I think they were largely separate but it's likely GMG North sent them stuff too. I recall watching Anglia post-GMG takeover (December 2001) and hearing Bob Preedy talking over a trailer for a regional soccer show. Hearing him say "On Anglia" was quite a novelty.
As for the YTV local idents: the replacement to the original aborted hearts idents that were to launch in October 1998 was being worked on with Carlton on board, until some point in mid-99. The prototypes produced were broadly similar in concept to the final ones i.e. live action film, then regional logo plus ITV underneath it on a spinning hearts background. Carlton weren't happy, got fed up of the bickering and walked; however, they took the prototypes to Lambie-Nairn to use as a basis for their own idents which were launched in September.
Presumably, the idents were hoped to be ready for a launch to coincide with the beginning of the Autumn season. With no sign of the idents plus Carlton launching their own versions, it would've been reasonable for GMG North to assume that the common network design was dead and so followed Cartlon's lead in designing their own versions.
Eventually, GMG, UNM, Border & Channel ironed out their disagreements over the prototypes. They were made lighter, both in brightness and atmosphere. UNM wanted the Anglia & Merdian logos in their natural colours, rather than monochrome yellow (which GMG decided was appropriate for LWT also). UNM also wanted the ANGLIA & MERIDIAN legends to be much bigger and so they were altered for those two stations specifically. Channel had launched their own take on the hearts theme earlier that summer (replacing the CTV logo) and wanted their logo to animate like it did on their existing idents, as well as retaining the music. Border wanted rid of their logo (for some weird reason). Clearly no one in the offices of high management at GMG bothered to keep the Northern presentation team in the loop with developments.
As for the design of the Yorkshire local idents: it shouldn't be assumed they were what would've been the final product. Although I think the spinning Chevrons would've been used for the background, they may well have used different styles and colours, like Cartlon's did (and to some extent, the Christmas idents).. Also, the music was identical on all of them and rather boring. Seems like it was knocked up last minute.
The Christmas idents would've been easier to make as they were identical, apart from the logo. Granada & Tyne Tees' normal idents would've required locations relevant to their respective regions for the film shots, plus the Yorkshire fanfare couldn't have been used. Clearly, these hadn't been filmed yet. I do wonder if the two note signature used on the Christmas idents was closer to what they were planning to use across all three stations on the standard idents.
As to the OP's question, it's a mystery to me too why Tyne Tees were allowed to retain their existing ident for local junctions whereas Granada had to use the hearts only. There are only a few differences I can see between Granada and Tyne Tees: firstly, Granada's ident was a lot older. Granada had several idents rather than just the one with a nighttime variant. Tyne Tees had recently suffered the terrible Channel 3 North East brand and maybe GMG didn't want its brand awareness compromised too much. The Granada arrow logo's official colour was white, up until that point, which clashed with the yellow hearts version. Tyne Tees' was yellow. Not that that stopped worse inconsistency with the new Tyne Tees idents produced in 2000; which are even more of a mystery, considering they use a redesigned TTTV logo and it was clear at this point that the hearts were here to stay and that the new idents would not be used outside of the ever-dwindling number of regional junctions.
It's a shame after all these years, such mysteries are still unsolved. You'd have thought by now someone would've turned up who had worked on these idents or was close enough to the operation to have known about what happened. Maybe someday, all will become clear, Don't hold your breath though.