Windows – Cannot install RDS-Web-Access

I'm trying to install the remote desktop web access role in server 2012, a simple task you might think, however whenever I try to do this, I get this error:

add-windowsfeature : The request to add or remove features on the specified server failed.
Installation of one or more roles, role services, or features failed.
The specified module could not be found. Error: 0x8007007e
At line:1 char:1
+ add-windowsfeature rds-web-access
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (@{Vhd=; Credent...Name=localhost}:PSObject) [Install-WindowsFeature],
    Exception
    + FullyQualifiedErrorId : DISMAPI_Error__Failed_To_Enable_Updates,Microsoft.Windows.ServerManager.Commands.AddWind
   owsFeatureCommand

This is from trying to install via powershell, but I get the same error via the GUI and using DISM.

This is a fresh out of the box server 2012 server. I have wiped and re-installed windows to no avail. I have tried using Dism with the sources switch to point to the 2012 media, same issue.
The server is connected to a WSUS server for updates, but I have added the registry keys so that it can use Windows Update for any feature content it needs, I have also moved it to not use the WSUS server and go straight to Windows update, same issue.

Other features install fine (RD gateway for example) but I cannot get RD web access to install.
I have also manually installed all the pre-req components (iis, asp.net 4.5 etc) and the error still occurs.

Any suggestions greatly appreciated.