p/n 60112035000 costing about £288 plus a mounting kit p/n 63512938044 at about £40. Manual.
You can make massive savings on the Meta DefComT alarm system by buying here: https://www.southerncarsecurity.co.uk/index.php?route=product/product&path=112_53&product_id=88. This is the exact same hardware, even the light in the dashboard works out of the box. The £40 mounting kit is still necessary as it includes the contact to detect seat intrusion.