Ok, one of our citrix servers decided it was going to bother the users with activation notices. This server was configured for MAK licensing at the time and had been working for some time. To resolve the issue, I installed the KMS client keys, pointed the office activation at our KMS server (which had already been setup previously) and ran a few commands to complete the process.
Here are my notes:
List of product keys for office 2010 http://technet.microsoft.com/en-us/library/ee624355(office.14).aspx
The following commands need to be run from the command prompt and you must run them from the installed product directory (office14 etc under the programfiles folder)
1. find out which products are currently installed
cscript ospp.vbs /dstatus
2. add the relevant product keys
cscript ospp.vbs /inpkey:<kms product key>
List of product keys for office 2010 http://technet.microsoft.com/en-us/library/ee624355(office.14).aspx
The required KMS Office 2013 key you get here http://technet.microsoft.com/en-us/library/ee624355.aspx#section2-3
3. specify your KMS server if you have issues with SRV records etc.
cscript ospp.vbs /sethst:<kms.dns.name>
4. activate the licensing by using the following command
cscript ospp.vbs /act
I had to install the MS Office professional plus client key, the MS Project professional key and the Visio key and everything looks good after that.