I've found a fix for removing the developer category.

Go to ~/Library/Preferences/

Open Terminal. You will need to convert the Spotlight plist file to XML (from binary) so you can edit it in TextEdit. The command you need is:
plutil -convert xml1 ~/Library/Preferences/com.apple.spotlight.plist

Open this file in TextEdit. Just before </array> at the bottom, add the following:

		<dict>
			<key>enabled</key>
			<false/>
			<key>name</key>
			<string>SOURCE</string>
		</dict>

Convert the file back to binary using:
plutil -convert binary1 ~/Library/Preferences/com.apple.spotlight.plist

Log out and back in again.