Seventy years old and it appears in better shape than many more recently made bomb shelters I’ve seen.
I enjoy seeing these older shelters when they turn up. Part of the attraction is that many of them were quite effective but were built, necessarily, using materials and techniques of the time. With modern techniques, materials, and equipment you could build something better, faster, and probably cheaper. But if all you have is 1930’s technology you can still build something like that. I find that a bit reassuring.