The DATCO at the time would have not had authority to declare open before 0800.
The pilot was cleared by ATC to contact London Heliport. His response to this transmission ended at 0759:22 hrs - just 38 seconds before 0800.
Maybe the DATCO assumed it would have been 0800 by the time he landed?
Not unreasonable.
Anyway, all that doesn't matter now.
What can be done to dissuade pilots from getting themselves into the position this pilot did?
What can be done to help pilots not get into that position?
It's an industry problem around the world and it ain't gonna go away on its own.
Is there a will in the industry to do anything about it?
Maybe not?
Maybe it's the elephant in the room nobody wants to talk about?