Mine is A23XX. IIRC the F 50 on it means Fazakerley, 1950 build. The book says there were 15,000 made at Faz, serial prefix A, and 2000 made by BSA fior the NZicon contract, serial prefix DA

Being about half way between 5thBatt and Bindi (two of the most dedicated owners of no8 rifles in this part of the world) I was lucky to snag mine from under their noses.