Looks like Sudanese knife from the Mahdist period or shortly thereafter. Attached below is another example from African Arms with the same bayonet blade type and form. My guess origin of a Khartoum workshop to near the 3rd cataract of the Nile in Northern Sudan near Dongola. I will attach a Dongola style curved dagger that I received recently. Take particular note in the similarity of the segments of bone and horn hilt with metal alloy spacers paired with the brass pommel. The shape of yours reminds me of some British naval dirks. The Nile was used by the British for logistics of troops and ammo during the Mahdist War departing from Egypt, eventually making their way to secure the Sudanese capital of Khartoum. Ian, a great knife in my opinion.
https://africanarms.com/gallery.html...ger-in-3-views
https://www.the-mansfield-collection...ola-dagger-488
-Geoffrey