I did as you @NorthernSands so had a new server and needed a new mapped drive as well as sims.ini (don't know why it's had the server name hardcoded!). This was the batch file i made that i got the technicians to go around and run in the holiday. I got the Network Manager to put the mappings parts into Logon script for staff.
Also i made the batch file available as a link on the intranet for those that had issues, mostly remote offices and computers that could not be accessed. The only slight issue was that the script needed to be 'run as adminstrator' in order for the files to copy to those locations. To make this easier for staff, i made a shortcut to the batch file. Then right click properties of the shortcut and advance properties has the option to 'run as administrator'. This then meant it could copy the files to those restricted windows 7 locations.
Now the new SIMS.ini refers to the S: drive, so shouldn't ever need changing again.
echo DELETING OLD S: DRIVE
net use s: /delete
echo MAPPING NEW S: DRIVE
net use s: \\SIMSSERVER\SIMSDATA
echo COPYING SIMS.INI TO PC
xcopy "G:\vik\sims\sims.ini" c:\windows\ /f /h /r /y
echo COPYING CONNECT.INI TO PC
xcopy "G:\vik\sims\connect.ini" "c:\program files\sims\sims .net\" /f /h /r /y
echo IF THE DRIVE WAS MAPPED SUCCESSFULLY AND BOTH FILES COPIED ACROSS THEN YOU CAN RUN SIMS .NET
echo SIMS SHOULD UPGRADE ITSELF THEN YOU CAN LOGIN