SKYbrary has an article on this here
SKYbrary - Strategic Lateral Offset
There's a link at the bottom of the article to the North Atlantic manual hosted by ICAO EUR. It contains the relevant details for obtaining a hard copy of the video produced by NATS.
The title is "Track Wise — Targeting Risk within the Shanwick OCA." The full video is also available on Youtube:
From the NAT manual: "
Like [the North Atlantic Operations and Airspace] Manual, [the DVD] is aimed at pilots, dispatchers and others concerned in flight operations in the North Atlantic. It follows the progress of a westbound NAT flight through the Shanwick OCA as well as exampling contingency and emergencies situations. While the operational procedures elements are specific to Shanwick, the majority of the DVD considers issues common to the whole ICAO NAT Region."