I would be amazed if they hadn't rationalised that when they moved Channel to smaller premises rather than building playout facilities?
It may be that Chiswick treats Channel as a sub region of Meridian.
If Chiswick is involved, then implementing an HD version of it should be easy, or at the very least providing an HD version to the islands (Meridian Kent HD for instance ?) which hasn't happened yet.
That's what makes me think Channel are still doing local pres, in their new building. It's not that complicated
if they are, I suspect a similar operation to a BBC English region, using the news studio gallery and servers for the pres facility too ?
Chiswick are indeed involved. Wales moved north to allow Chiswick to add Channel to their regional opt play-out. All regional chains are now fully HD and downscaled for SD purposes as I understand it.
I work in telly, I sometimes get time to watch telly. More of a technology geek than a presentation geek!