No Problem.

Had a closer look and the key way is largley intact. There is a tiny chip in the centre of the keyway.

I propose I will get a second hand harmonic balancer / hub as it looks like the current one is damaged. I can get one for $50 NZ so its not a major cost.

If this proves to not fit properly, I have two options.

Second hand crank - just getting avaliblity and price locally.

OR

Engine swap - Can get one pretty cheap.

My question is, in terms of effort is change the engine, or the crank more involved?

From what I can see and engine swap is straight forward, the crank swap is not.