Just letting you all know that I've finally written a script that does what I want it to do with regards to proxies...in case anyone would like to know I've pasted the code below..

Code
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DIM $SUBNET
$SUBNET = SUBSTR(@IPADDRESS0,1,8)
If $SUBNET = "Your IP Address"
$key = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings"
WRITEVALUE($key,"ProxyEnable","1","REG_DWORD")
WRITEVALUE($key,"ProxyServer","proxy:8080","REG_SZ")
WRITEVALUE($key,"ProxyOverride", "<local>", "REG_SZ")
Else
$key = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings"
WRITEVALUE($key,"ProxyEnable","0","REG_DWORD")
EndIf
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Thanks to everyone who responded...much appreciated.