Thank you for the interesting replies. I have found that the steel oil barrel was used for shipping oil in 1902. Very interesting link-
http://aoghs.org/wp-content/uploads/...tent-AOGHS.jpg
The first oil well in Kenya was drilled 1960
Detlef, thank you for the information on the shield. I have that publication and have checked it.
In all my jumble it can sometimes be hard to see the wood for the trees.
Gav, any more information would be good. Like you I have read of and seen examples of East African steel shields from the earlier part of the 20th century. Like the development of steel drum and decline in wild animals I should think the steel shield has been around for some time.