Thanks again for your reply 
Last couple of questions if I may before I go shopping - looking at the ‘magnet sensor links’ you kindly supplied it appears they are a two wire installation yet the extension port at the back is 4 pin. Which holes will they go into or does it matter. After following your advice it will work best for me to have the magnets in the closed position…will I need to update the firmware to over-ride the inbuilt laser and use the newly installed magnets externally located or is everything still as per the post in this community (Gate Installation) and your reply Nov '16
Thanks again!
Paul