All NPL fields excluding 1 are all council fields so, they need to be left open for general public access and use. I drive past that field daily as, I live in the area. People walk their dogs etc on it.
You are dreaming. That is not the case at all, they do not have to remain open to the public, and I have yet to see gates left open anywhere, this would have to be the exception to every other NPL field around if olympic leave the gates open.