ITV abandons the South Bank

Not sure those plans got that far. The South Hall separation made huge sense in development terms, as it provided good isolation between the production and residential zones on the site. In particular it helped avoid 'noisy neighbour' issues... TC4 would have been very close to apartments...

GMB likely to be moving Monday 16th April: https://twitter.com/Lauratobin1/status/974925330690510860?s=19

I doubt they’re basing it all around the weather presenter’s return from maternity leave.

She is returning for the launch of the studio...

Not just the weather presenter, but that when it's likely Piers and Susanna would come back from their Easter break.
Phillip and Holly come back then also, so This Morning will probably launch same day.

So a picture of the new TM set was put up on Instagram, guess they’re trying to keep everything as similar as possible

I don't see why they wouldn't/couldn't use that Viz Window technology (it was owned bt Viz at one point IIRC).

Basically the same idea as the "in front/behind" switch that is used on green screens at election time, except this is smart enough not to need a physical switch.

Not a huge fan of the new This Morning studio, it looks like the cheap re-recreation that they took to the NEC in Birmingham. Looks like we’ll have blue lighting instead of the old warm white lighting, and there looks to be two smaller sofas instead of one large one.

I think they would have been better off with a new studio concept entirely, instead of recreating the existing look. Although I do see why they’ve tried to keep some consistency.

I think the blue lighting is probably just a test and won’t actually be used, same with the sofa, it looks just like the center part is missing, as you can see there’s no arms on the sides nearest the middle

What makes you think there will be blue lighting in the new look? That could easily just be an LED test either testing the lighting or the lighting desk connectivity. I'd hold fire on any judgement until you see the set on-camera...

But why would you want to use green screen in a studio if you didn't have to? The limitations on keying (colour of clothing, props, cooking ingredients even) would be a pain in the proverbial that you didn't need. Minimising green spill from that many windows (particularly when they are so close on the camera left side) would be a challenge. Last thing you want is green spill all over cookery.

Also - This Morning is a 'real people' show. Sitting them in a room filled with green windows would be a really un-natural experience, compared to screens, where they see what the viewer at home sees.

Plus if you are using an AR/VR system to render the view, you'd also need camera positioning and sensing gear, plus cope with the rendering delays. Again - more problems to solve that you don't need to with real screens.

I'm surprised they didn't set the screens back from the set so they could keep a parallax effect when the cameras moved, that would have kept more of a sense of a real view. Presumably they are space constrained because of the sharing of the studio...