Deleted analyst still able to logon to LANDesk console

One of our analysts left and so his account was deleted from the LANDesk list of users.

Now he's returned we've had to setup his account with a new unique username as I assume the backend database still retains his old record for historical and reporting purposes.  Our standard format is <first initial><surname> with the new account being setup with <first initial><surname>1.

Now here's the question that I'd like to see if it can be changed somehow:

Even though the record in LANDesk user managment is no longer there, he's able to logon with the old account name but once logged on can't do anything as it informs him he has no permissions to do anything.  Is there a way I can stop him from being able to logon with the old username permanently.

Thanks, Paul