Server 2012 R2 Activation errors - OEM_SLP

I have inherited a Dell Power Edge R320 server running for a client and it is complaining that it is not activated.

I have gone through the activation process by phone using the automated service and it complains that it is not genuine.

slmgr -dli 

shows the following:

Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.


Name: Windows(R), ServerStandard edition
Description: Windows(R) Operating System, OEM_SLP channel
Partial Product Key: 4GB43
License Status: Notification
Notification Reason: 0xC004F059.

There was a suggestion that MCADiag would shed light on it but that states "Validation Unsupported OS".

There are also a ream of event ID 1058 "Installation of the Proof of Purchase from the ACPI table failed. Error code: 0xC004F057" warnings in evnent viewer. There is a suggestion from Dell that a reg hack will remove these errors but I do not think this will solve the fact that Windows in not activated.

Has anyone seen anything like this before or have an idea about how to go about resolving this error? I am really concerned that the server will stop responding at some stage due to the license. I was under the impression that OEM did not have keys anymore and the chip on the BIOS stored the license information so not sure how I can change the product key or force it to refresh....

The server is running as a Hyper-V host.