I was thinking about the Sudanese possibility as well Colin. Perhaps a member can make out something of the script? The crescent and star symbol seen on the blade was of course common in the Madiyah and Khalifa - see attached image of the Mahdi's tomb taken in 1936.
Of course that's far from conclusive but I just wanted to illustrate the possibility.
I happen to agree with Colin about many of the thuluth items from Sudan and their likely period of production. Although that's not a judgement on this specific piece.
