You can cobble together a quick fix using a bicycle brake cable, a cable clamp (like you get on MTB V-brakes) and an 8mm socket. Fit the cable in the lever as normal, and thread the other end through the socket (through the square side, so the tapered end will sit in the cable stop on the cases) and use the cable clamp to lock the cable in the clutch actuator arm. It's not pretty, but it works, and can get you back on the road without having to wait for a cable to be delivered
Mick