Update in 2020: Sometime last year they changed the pregate area around. So instead of coming out the exit gate as shown in this video, that is now the entry gate, and vice versa. Its exactly the same until you pull off the main dock road. Thereafter, instead of hooking a SHARP left, you now carry straight on and around the back. Eventually exiting what used to be the entry. You'll see. Its very easy & straightforward.

Your first visit to Southampton Container Terminal as a truck driver can be a daunting prospect. So run through it with me first. It just might help familiarise you to the inner workings, before you get there yourself.