Nice Collection. What does AECO stand for? I have a few SA Bayonets. I have a Pattern 1907 with South African Police (SAP) mark and a chromed pattern 1907 with the Arrow U stamp. I have attached a photo of my 1896 Transvaal Bayonet. I don't know if you would consider that a South African bayonet or not. I travel to South Africa a lot and I collect Boer War and South African military and Police items
The bayonet is marked with Natal Volunteer markings. It is probable that they were originally supplied with the Swinburn rifles since the markings are the same, but they also fit the later Martini Metfords MkII.
These are some examples of the markings that appear on typical Natal Volunteer Swinburn rifles and carbines. The sawback is also marked JKL, a marking which appears on at least some of the Natal Volunteer bowie knife bayonets!
I don't know for sure, but on the information currently available one can probably make an estimate;
1) The bayonet appears to be a commercial version of the British Pattern 1875 and is thus probably a bit later.
2) The Natal Volunteer marking on the bayonet is what I believe to be the later version of the one found on the Swinburns but predating that found on the Martini Metford rifles which the bayonet also fits. I thus believe that it is safe to assume that it originally came with the Swinburn rifles.
3) I understand that batches of Swinburn Rifles totalling 400 were sent to Natal over the period 1875 to 1878.
Here is a soldier of the Royal Durban Rifles, with his Swinburn Henry rifle; it looks as if the bayonet is one like yours. I previously thought it was a pattern 1887 sword bayonet, which would make the picture 188os; but now I realise if it is a saw back bayonet then it is 1870s.