According to the
band's store, it's a design by "Herds Of Birds". (I just noticed that you actually appear to have used the image from their site, so you probably know that already). The site for Herds Of Birds is not yet open, but the cached version leads to their
store where it says that "Herds of Birds is the pseudonym of UK based illustrator and designer Matt Canning ".
There's an email address for him on
his site. But I would guess that it was more of an illustrative design, rather than trying to be real instructions (hence the lines used and the lack of arrows). Obviously he knows enough about origami to make a design that works, though.
I would suggest making a mirror image of the model, because the back is relatively clean (compared to the front).
As for the swivel fold, it obviously relates to the pleat in step 3, so play around with that, because my swivel fold didn't need any fudging. The fold from step 8 did need adjusting, though.
Also, just a note, when you cross post, you should mention where else it was posted and give a link if possible. That way, people don't repeat information that was posted by someone else. And everyone has access to all the replies, etc.