You know what, I think you might be right about it being the JArthy.
There is a better shot of her here: http://www.dailymail.co.uk/tvshowbiz/article-3604742/Tom-Hiddleston-dresses-casual-lunch-mystery-brunette-tipped-007-Daniel-Craig-quits.html
And here are some old pics of her. Compare the top left semi profile with the large pic of her in the DM taken from the same angle: http://tommyemma.tumblr.com/post/87702090302/isnt-that-jane-arthy
I think it is her - and no nose job! There aren't many pics of her full stop and most are full face so it's no surprise she looks a bit different viewed from the side.