I don't know of a column that would show information if the agent has been disabled within Protect. Basically this is because the way our agents work is that they update the console with information when they check in or finish a task. There isn't actually real-time communication always going on between the agent and console (since that would probably overload networks).
Is only the threat protection disabled? Or the agent entirely?
If the agent is entirely disabled, you could attempt forcing an agent check in of the agents by going to View > Machines, select any agents to check, right click > Agents > Check in request. If they fail to respond it could be an indication that the agent has been disabled on the system. (Of course it could also be that the port for sending the command to the agent is not open or that the agent is unable to check in.)
It sounds like you should look into creating a script or something to disable AVG toolbar on the systems.
You could also try adding a 'Never Allow' exception into your agent policy threat settings for AVG toolbar. That might get our agent to stop AVG toolbar from being installed/enabled. You'd just need to know the files/folder where AVG toolbar files go. You can read more about how to set this up in Help > Contents > Agents > Configuring An Agent Policy > Configuring Exception Lists.
I hope that helps.