search google and this website:

Tmatboey Lodge,
Kulen Promtemp Wildlife Sanctuary, Cambodia

Tmatbuey is a community which protects an area of tropical woodlands within Kulen Promtemp. The simple lodge is where most eco-tourists are based when looking for wildlife.

personal experience

I spent a week in northern Cambodia, including three days in the Tmatbuey area specifically. 

the lodge

The lodge is fairly basic, but comfortable. When you are doing the tours, most of the time here will be in the heat of the afternoon, when things are pretty quiet. However, the immediate area around the lodge is also productive for birds.

Updates
Throughout the virus I am working in Australia on and off as local borders close, mostly as Expedition Leader in the Kimberley (May-September). If you can't go travelling until everything settles down, then until then, here I am doing online guided walks for Noble Caledonia and online lectures for Silversea.