Gustto for sure, based on the hardware. I have some of their bags and the leather is incredible. I don't know the size she is carrying, I think the Setala only came in Large & Medium (maybe saying 'small' scares buyers). They show up on ebay all the time, here is a listing for one. Good luck on your search.
There's only 2 sizes that I know of: the smaller one Rumer's carrying and the big one. The big one is ginormous! My 2 year old could literally fit into it, so I returned it. And ITA, Gustto leather is TDF!!
I have the Gustto Setela in the large and love it to death! Everyone has the own opinion on what is big and what is not. It is a bigger bag but the way it hangs and the way the leather is so smooshy it doesn't seem to be big or look huge. I haven't had anyone comment on the size of it as of yet and I have always carried big bags and usually get a comment or two. ALso my Setela is very light for the size it is. It is for sure the lightest large bag I have ever owned and I adore it. I am looking for more colors now and am hooked.....