There are two vents holes - one on each side of the case just in front of the handset. These mean that the phone is a tropical variant.
Other part numbers found in the phone are also prefixed with a letter N which confirms ETL.
Conclusion:- Made by ETL but sold on by GEC. This used to happen quite a lot in the UK.
The diagram is dated around 1956.
Can be found around the world. The one pictured her was found in Australia.
It's not quite as Brown as it looks
Last revised: January 30, 2021