Notes:

All of the above options are the DEFAULT on Google, some explanation is provided here.
Restrict to country does exactly what it says. If you want worldwide results set the option to "--", to restrict to UK results only set this to "UK".
Filtering activates or deactivates automatic results filtering, which hides very similar results and results that all come from the same Web host.
Safe search is a boolean value which enables filtering of adult content in the search results.
The higher you set the number of results to be returned the longer the script will take to run, the maximum limit (set by Google) is 10.