Ok ive figured out how to fix it.
Windows Server doesnt come with a functional version of direct X and the one that AMP tries to install either fails or doesnt include what is needed to run Icarus.
After trying to run the server manually from the explorer i got the error:
You need to have Direct X runtime installed.
Tried to download the installer from Windows and it failed to download because Windows Server hates it for some reason.
Found this download link on the Microsoft site:
https://www.microsoft.com/en-pk/download/details.aspx?id=8109
Downloaded and installed it. Installed an Icarus instance and ran it.
New error codes finally!
I found that you cant run the instance from the a folder in the parent C drive.
You need to set your Datastore to a location with full read/write capabilities.
I had a second SSD in my server labelled S:
Created a new Datastore there, created a new Icarus instance in it, and VOILA!
The server updated fully from SteamCMD and ran successfully.
Searched for my server and connected in the game sucessfully.
Hope this helps. What a massive hassle to get one game server working.