The seller has furnished me with additional information...
Apparently it was obtained in Nigeria....some years ago...by a Merchant Marine. He was told that the sword was 'NUPE' and he (the seller) insists it is 'battleworthy'. The Nupe had constant conflict with neighbouring tribes and according to my research were skilled 'bronze casters'. Seeing as Dahomey was one such neighbour....Rick's suggestion of Dahomey as the sword's origin seems 'not so wide of the mark'......begining to seem a 'good call' Rick