Not sure what this 1940s telephone was originally used for, some sort of radio telephone link I guess. Anyway it seemed ideal for conversion to a bluetooth phone. With the handset down the original loudspeaker fitted in the dial aperture is loud enough to be heard clearly in a quiet room. I though some extra amplification might be needed, but I got lucky.
The clear glass bezel was in my junk box and works beautifully to allow the bluetooth earpiece blue/amber LED to be seen.
A simple project, but very pleasing.