Plenty of Thames idents on Man About The House, George And Mildred and Bless This House, all on Paramount.
Central idents sometimes shown (both front and endcaps) on Family Fortunes/Bullseye on Challenge.
The first Catherine Cookson drama "The Fifteen Streets" has the 1988-89 Tyne Tees ident burned into the start, as shown on UKTV Drama, however the time I saw the start of this there was only a 2-frame flash of the fadeout.
I've bought the rereleased DVD from Network and I can say from the disc that I've watched so far they've kept the Liquid Gold frontcaps and endcaps. I had Series 1 on DVD from the GR/N/D/ / Cinema Club version but they went to all the trouble of removing them.
Chances are that any external company which takes on archive material, be they TV companies or DVD sellers, are going to leave the frontcaps intact if that's what they receive on the master copies they receive. Reasons being that (1) it's too much like hard work and too costly to make professional edits for a fairly minor thing, (2) nostalgia reasons and (3) a potential copyright backlash (generally companies will be told not to alter the source material in any way, and removal of copyright notices could be seen as such).
On the other hand of course, internal releases will be altered, as it is in Granada's interests to forward its current branding wherever possible. Not a new thing; when Tyne Tees released a Bobby Thompson video in the early 90s they removed the 1980s branding from the tape.
That's only a recent thing though, they used to cut them out. I am slightly puzzled as well, as the frontcap even appears on the later episodes, which were made & aired after frontcaps were abolished.
The Region 1 DVDs of Mr Bean have the 'skyline' Thames frontcap too, apparently, which is weird as the first one was shown in 1990, after frontcaps went.