This AutoIT script literally toggles the proxy on and off and reports which one is active, i nicked it off the AutoIT site ages ago. The teachers can understand this one. Ive seen less elegant solutions by other Techs at schools I have taken over the running of.
Try it, you might like it.
$ProxyEnabled = RegRead('HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings','ProxyEnable')
If $ProxyEnabled = 0 Then
RegWrite('HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings','ProxyEnable','REG_DWORD',1)
MsgBox(0," Proxy Toggle","School Internet",2)
Else
RegWrite('HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings','ProxyEnable','REG_DWORD',0)
MsgBox(0," Proxy Toggle","Home Internet",2)
EndIf