Oncidium cavendishianum...

Finally I was able to identify this species as Oncidium cavendishianum. The inflorescence was a key element to determine its name. Onc cavendishianum produces a "lateral paniculate, many flowered inflorescence", to quote Hamer, while Onc bicallosum produce a "simple raceme sometimes a branched panicle of yellow flowers".

Done