Ian, you did not give us all the details about your computer. It will help if you give us at least the last four digits of your computers serial number. right now it appears as if you have a late 2006 iMac. For that the display is Apple part number 661-4020 and the panel is either a LM171W02 or a LM171W02-TLB1 and it will fit the following:
iMac 17" 1.83GHz Core 2 Duo (A1195) - Mid 2006
iMac 17" 1.83GHz Core Duo (A1173) - Early 2006
iMac 17" 2.0GHz Core 2 Duo (A1208) - Mid 2006
iMac 17" 2.16GHz Core 2 Duo (A1208) - Mid 2006
A G5 is not compatible. Just for completion sake, that is part number 661-3598 which is only compatible with
iMac G5 17" 1.6GHz G5 (A1058) - Mid 2004
iMac G5 17" 1.8GHz G5 (A1058) - Mid 2004
iMac G5 17" 1.8GHz G5 - Mid 2005
iMac G5 17" 1.9GHz G5 (A1144) - Late 2005
iMac G5 17" 2.0GHz G5 - Mid 2005