Labelled simply “Plateau Mining Co., Ecuador”, this specimen came from a collection acquired by Richard Bell. Obviously, Plateau Mining Co. isn’t a locality, but a company, so the starting point is simply Ecuador.
After a bit of searching, I came across a mining professional, Byron Granda, who at one time had worked for Mizaña Mining Co., a subsidiary of Plateau Mining Co., itself a branch of UK-based, the Robertson Group. His activities included being responsible for gold exploration within the districts of Nambija and Portovelo.
Nambija in particular, in the south of Ecuador, hosts some skarn deposits. Alfredo Petrov has a couple of photos of gold associated with skarn minerals in Mindat, and the matrix of these look very similar to my specimen. That locality is the Sultana del Condór Central Mine, Sultana del Cóndor deposit, Nambija District, Zamora-Chinchipe Province, Ecuador.
Now of course, there is no certainty, but the availability on the mineral collector market of gold specimens from Sultana del Cóndor, means that there could have been additional specimens that made their way to the UK. So, my specimen will be labelled as possibly coming from this locality.