Nearly, the actual ladder is at the far end of the quay, out of shot to the right. It is approximately the same height but at low tide there is still enough water for a boat to float whereas at that ladder they land on the mud.
The boat in the picture is a fishing (more likely prawn/crabs/lobster) boat. But in front of it is a dive boat with a lift on the back. The blue tarp is protecting the hoist motor from the elements.
This picture also gives you an idea about the sort of boats that get used for diving in the U.K. Typical day boats are substantial 10 to 12m work boats, not the sort of thing that you pick up at the Boat Show for personal gin and tonic drinking.