Went to Barnes & Noble and picked up the Doctor Who Magazine Special 2016 Yearbook. There’s a whole section discussing the Abbey Road photoshoot with Peter, Jenna, and two Daleks. There’s also some rare photos of them rehearsing the famous pose within the studio’s forecourt.
My theory was right about the DWW 29 1F referring to Clara’s demise since her birthday is supposed to be November 23rd while Jenna already had her birthday on April 27th. With the whole “Paul is Dead” rumor (loved Peter’s expression of calling it ‘total bunkum’), they wanted to add some sort of myth into the DWAR (Doctor Who Abbey Road) photoshoot. And since there was such a buzz of Clara’s death, it was only natural to put that license plate on the Volkswagen Beetle.
Oh, and I deliberately added Peter’s quote about playing George Harrison with the side-by-side comparison of the VW Bug (between 1969 and 2015) since, well, George is seen in the photo! :)
Another thing the article briefly discussed was how a photo was taken of Peter with his left foot forward (like John Lennon), but then he switched it to be in line with Jenna. He was actually told to do that by both her and the director, and many fans are coming up with different theories of why.
One theory could be this: Clara was becoming more and more like the Doctor, with proof of that from the episode Flatline, all the way up to her supposed death in Face the Raven. With the final outcome of Hell Bent, the explanation of their identical foot/leg pose could be this:
Clara Oswald is following in the Doctor’s own footsteps!
Doing this photoshoot the same day as the premiere of Series 9 and The Magician’s Apprentice, it was a very clever (and awesome!) marketing promotion.