Jon, I don't live in your part of the world so I don't know what traps are available and appropriate for your situation. Its important to find methods of control that, used in conjunction with cleaning up and closing off buildings, allow for as humane and immediate control possible, and use methods and materials you are prepared to live with. The following site may be helpful to you. It is not cheerful reading by any means yet does seem to address many important considerations. http://www.ufaw.org.uk/rodents.php