I found the shot of her in the same bra (from behind) on her Insta.
😳
I was right - the back band is waaaay too small. Look at how much it’s riding up on her back. It should be horizontal and really quite low on her back (it’s a little-known fact, but the back band does all the hard work on a bra - a well-fitting, well-designed back band should hold up your boobs almost without the need for shoulder straps. It does 80% of the lifting, if it’s the correct size).
With a badly-fitting back band, you end up using the shoulder straps to pull the cups up (and if the cups are too small/too big, the boobs end up being crushed in the cups).and that puts pressure on your shoulders and back. But, as we all agree - it’s almost certainly deliberate on Louisa’s part.
Sigh.
Update: having looked through her insta, it’s kind-of obvious that she wears poorly-fitting bras in her day-to-day life. There’s shots of her trying our denims in a fitting-room, and the bra is killing her boobs. Plus other shots of her out driving coffee etc, and it’s pretty clear the bra is too small. Oh well.