The oldest article I’ve noticed on this so far is from 2013; at that time the number of housing units was higher. Local housing has already encroached on the site, and based on some of the other shots I’ve found of it, grazing is done on the top.
The site was used as a training site in WWI (see the wiki entry up there), and they dug all over the hill, part of their training for trench warfare. The site has never been scientifically studied; it would be nice to work out something — the developer would get to ring the whole site, but at some larger minimum standoff, and would have to pay for the research in the areas to be constructed. Naturally there would have to be more units.
[Aerial photo by Alistair Reid]
http://oldoswestryhillfort.co.uk/wp-content/uploads/2014/02/P1220030a.jpg
I agree. In poking around for images it appears the fort is on the edge of a city. Working out a trade of development rights for funds to research the site would be a win for everyone.