I'm sure it has a more specific name somewhere, but I haven't heard it yet. Jenna wore this jumper for her first photo shoot with Matt Smith. If you see one you think might be it, just remember that the order of the pattern varies, so it might look slightly different and still be SA.
Worn in: Matt Smith Photo Shoot
Sessun Knit Contrast Collar & Cuffs
I've seen it described as Tomasso Navy. It is extremely rare, but you only see the collar, so it's not hard to get away with an alt as long as the color matches the skirt. These came up for sale recently on an Italian site, and I barely missed it. Still mad!
Worn in: Nightmare in Silver
Oasis Yellow Faux Collar Jumper
These come up fairly often, but they still always seem to go pretty high.