The three menu entries MPlayer, HEAT and WON I never used but always hated them. I found that you just got to go to your UnrealTournament.ini (UT not running) and search this part:
[UTMenu.UTMultiplayerMenu] OnlineServices[0]=LOCALIZE,MPlayer OnlineServices[1]=LOCALIZE,Heat OnlineServices[2]=LOCALIZE,WON
After you deleted the values like this:
[UTMenu.UTMultiplayerMenu] OnlineServices[0]= OnlineServices[1]= OnlineServices[2]=
these entries are removed from the Multiplayer menu when you start UT again.