I thought it worth giving an update on this. It appears that you cannot verify the local administrator account on the PMP server. The support guys are looking at this and may have a solution.
The Password manager Server is a windows server obviously and one of the things we want PMP to do is control the local admin password. It appears that currently that's fine for all of my servers except the Password Manager front end server itself.
To prove this I can verify the local admin credentials on the Slave
server from the Primary web portal and the Primary local admin
credentials from the Slave server web portal. But on each if I check
the local account, i.e. check the local admin account password of the
Slave Server whilst using the web portal from the slave verify fails.