CHANGE USER DISPLAY NAME USING POWERSHELL

I have recently extended a web application to enable Form Based Authentication.  After a few days I noticed that user display names are showing in the following format:

i:0#.f|webbworldfbamembershipprovider|dave@webbworld.local

I would prefer to see ”Firstname Surname” format.  I can use the Set-SPUser PowerShell command to change the display name.  Here is an example of how this works:

Set-SPUser “i:0#.f|webbworldfbamembershipprovider|dave@webbworld.local” -Web http://intranet -DisplayName “Dave Webb”

Now the display name is shown correctly.