Casualty

It's the right shape for the Holby City building at Borehamwood, but seems to have too many floors.

Agreed - the Borehamwood building looks fairly different. I reckon it’s just an aerial shot of Roath Lock with some bits of CGI, as David said. They’re definitely meant to be in the same ‘universe’ - there are a lot of Holby references to Casualty and Casualty references to Holby, including crossovers.

Casualty sticking with a 2:1 ratio for a second episode, whereas Holby City went back to 16:9 after one at 2:1.

I'd imagine they're most likely keeping it then.

So definitely sticking with 2:1 for good by the looks of things. And now they're also doing on-screen pop-up text messages a la Hollyoaks...

I don't think there's anything wrong with doing on-screen pop-up text messages, and I also don't think so far the concept been limited to Hollyoaks. Texting is a part of modern life, and subsequently a realistic mode of communication between characters. It can often be difficult to read a filmed phone screen depending on how it's shot, plus from a creative perspective it means an ugly lingering shot on a phone long enough for slow readers to take in the information on the phone display at the expense of a nicely directed sequence where we see the reaction of the character reading or typing the text. So personally I'm all for it, as long as the graphics themselves aren't distracting.

The concept was used on Sherlock about 10 years ago. It’s not particularly new.

At the start of the episode, the CA mentions how masks and PPE were used "with dramatic licence". What exactly does this mean?

It means they're probably not wearing their masks properly - Holby is the worst I've seen for masks around the chin, even though for years hospital dramas have had actors speaking whilst wearing them without giving it a second thought.

See below

Artistic license
Artistic license is a colloquial term, sometimes euphemism, used to denote the distortion of fact, alteration of the conventions of grammar or language, or rewording of pre-existing text made by an artist to improve a piece of art.

Oh dear. Someone's seen fit to slap "Line of Duty Next Sunday 9pm" over the cold open to Casualty.

I thought they'd got that sort of thing out of their system after trying it a few years back...

Being discussed at https://tvforum.uk/tvhome/bbc-one-promo-dog-returns-46815