Looks pretty typical! You'll have to find someone to weld it up and re-cut the first few teeth, and then be careful to engage the gear before kicking. In my own town, most businesses capable of doing jobs like this have now gone.
I know it's of no use, but when I restored a BSA Sloper in the early 1980s one of the local motorcycle wreckers had drawers of new-old-stock BSA gears, including the ks gear. I doubt I paid more that a couple of dollars!
Leon