How I wish I had asked my mother about it before it was too late. From the date stamp, it is possible that it was her mother's - but something I do recall her saying was that the only possession she had that had been her mother's was a saucepan lid! This stuck in my mind because it was so bizarre, and also because there was an old saucepan lid which she always kept.
The finer details don't matter, suffice to say that my grandmother was the second wife of my grandfather. Ultimately two of the much older sons from that first marriage ended up living with my grandmother and grandfather and they, allegedly, claimed everything when my grandfather died...well, all but the saucepan lid.
Unfortunately, I will never find out the story of the hansom cab (or the saucepan lid) because the last one standing, my mother's sister, has no memory of it at all.
So, the history of the brooch must begin with my mother, but that still leaves a lot of years where it was presumably enjoyed by someone else. Hang on while I call a cab...