Claire,
That is lovely. Can you show the interior, and is it lined? This is just a guess on my part, as I cannot feel or see it in person. Perhaps 1930s, circa early - mid decade. The style looks right for that time period, and also the materials. I have run across a small number of 1930s garments (and 1 or 2 hats) over the years that used leather as trimming, and memory serves me the leathers were metallic gold or silver.
I love the way the designer used the leather as flowers. the jacket reminds me a bit of Schiaparelli in overall look.
I just get that sense, but of course it is just a guess.