That's the problem, you are looking on google and not at the right place. If you wish to be an expert of the subject then start looking at the right place.
I attached the image of the type of longicornu above, does it match with your so-called longicornu? You can see on the type the front lobe of labellum is not a separate roundish structure as in your plant, but wattii has.
I also attached the image of a type of wattii, yes it doesnt really match for one big reason, the frills of the front of the labellum of type are broken, it was there, I have seen the specimen myself in London. Same was written by Gunnar Seidenfaden when he revised the Dendrobiums.
Wattii is known from China and Assam so obviously it may not be hard to have it in Nepal.
I have Raskoti's orchids of Nepal and the plant in it is also misidentified I think.