At the 25:24 mark, there's a QR code on the table at the cafe. If scanned, it will now take you to the BBC Doctor Who website. Originally, it was redirecting to the set designer's own website.
On Michael Ball's BBC Radio 2 show (on air: 12 Feb 2023), showrunner Russell T. Davies said: "I sat here and I watched episode 4 last night and I think it's one of the greatest things I've ever made in my life, so I'm very, very happy with it."
The choreographed movements and words Hilary Hobson mouthed on camera - not the dialogue the 73 Yard Woman says to people to make them run, which Russell T. Davies is happy to leave to the viewers' imagination - went along the lines of "Bless you, thank you so much (shrug); that's so kind of you, when you gave me that little thing (circular hand movement), it was just so precious (hands to heart); how am I ever going to repay you? (big shrug) But we'll think of something."
The pub is called 'Y Pren Marw', which translates as 'The Dead Wood' in Welsh.
Several of the cast members of this episode have previously had roles in Doctor Who spin-off media. Maxine Evans played Helen Sherman in the Torchwood (2006) episode Countrycide (2006) and has also voiced characters in the Big Finish audio dramas Gallifrey (2004) and Torchwood (2015). Sion Pritchard has voiced characters in the Big Finish audio drama Class: The Audio Adventures (2018). Siân Phillips has made appearances in several Big Finish audio dramas, most notably Jenny - The Doctor's Daughter (2018), in which she voices COLT-5000.