Vanity sizing gets more and more ridiculous with each passing day. Years ago, I was considered a medium at US size 4 (UK 8). Two years ago, it magically became S. Now, size 4 is apparently XS. My weight/proportions have not shifted whatsoever in this period. I think they've started changing the numbers too, because size 4s have stopped fitting snugly on me. And I think the increases to accommodate width are geometric as you go up the sizes, because a size 8 to a size 10 is definitely less fabric across than a size 10 to size 12. And based on this wannabe model's pictures, she's usually wearing something two sizes too small, so I can see how this is supposedly a UK 12 (edit: 16).  Sizing numbers only really make a difference to fats who know they're inferior, anyway. I'm sure you wear anything UK 12 far better than any of those bumbling idiots could ever hope to.