Thank you for the suggestion but I found a way to resolve this without regenerating my world - see below if interested
This was helpful in identifying which POI's I needed to get added to my world - thanks!
I was only missing DFalls_Military_Bunker in my world and have managed to add it to my world without regenerating the entire map - see below if interested
Unfotunately most tutorials are out of date (I already seen the link you provided just before you posted it 😁) and only work on Alpha 19 or below because the Prefab menu was removed (usually you'd access this by pressing Z then K while in debug mode)
I have however found an updated tutorial for Alpha 20 which allowed me to add the POI to my existing world (YouTube: 7 Days To Die Alpha 20: How to Add, Remove or Replace POI's)
A few extra steps for me as I had to copy the world files to my PC to be able to edit them in-game and then had to copy the files back to the server once finished.
Steps I had to take:
1) Copy the world files from the server to my PC running the game.
2) Open the game and select Editing Tools - World Editor
3) Select my world that I copied from the server
4) Placed the POI in my world, saved it and exited the world editor
5) Delete the chunk which the POI was placed in to allow the server to refresh that chunk on startup
6) Copy the world back to the server
I have since tried to start "The Reward" quest again and this time it has not cancelled itself and the waypoint is in the exact location where I placed the POI in the world with the tutorial above.
Happy our server didn't have to wipe again!