Note: The listed rates are not necessarily complete - this what I have identified to date.
All errors are mine alone. Additional information and any corrections are welcomed
Sources and Acknowledgements
I have used multiple sources to identify the various postal rates, including cross referencing.
The major sources have been
Below I have listed books for specific colonies/countries where a significant amount of information was available.
Brown, J. Indian airmail Postage rates until 1956. The India Study Circle for Philately. 2000
Ferguson's Ceylon Directory. The Ceylon Observer Press. Colombo 1936
Furfie, M. British Civilian postage rates of the 20th Century. Michael Furfie. Ashford. Middlesex 2000
Hopson, S & McCloy, B. Seychelles: Postal history and Postage Stamps to 1976. Indian Ocean Study Circle 2002
Nicholson, MP. Postal History of Nigeria 1900-1936. Somerset. 1985
Stotter, DA. The British Post Office Service in Morocco 1907-1957. Postal History Society & British Philatelic
Trust. London 2007
It would be difficult to list everyone who have provided me with assistance. However, I would like to acknowledge the following individuals. I apologise in advance to any one who feels they should also be listed and aren't (Feel free to contact me)