No worries - I am too; I've just been shown what to do:
Probably the easiest way is dragging the 'regedit.exe' file from inside /YourUser/Library/Application Support/CrossOver (or Games)/Bottles/BottleName/drive_c/windows into the icon (which should launch the .exe file) and then once you're in there navigate to HKEY_Current_User~Software~Wine then right click Wine (the folder on the left) and click New~Key. Name it DirectInput. Right click the area to the right hand side and New~String Value. Name: MouseWarpOverride then hit enter then double click the string and enter force as the data.
If that doesn't work open up user.reg (in the BottleName folder) with your favourite text editor (I'd use BBEdit) and search for: [Software\Wine\X11 Driver]. Just above this paste:
[Software\Wine\DirectInput] 1264890967
"MouseWarpOverride"="force"
which will do the same thing.