Images of property used editorially

Thanks load folks - great advice as ever. And an interesting debate.
Think I'm even more confused now!

Why?

Well, the properties in question are actually 'English Heritage' (probably similar policies to National Trust I suspect). However, the places in question have no entrance fee, and one of them is in fact basically a ruin! (Not well maintained to command a fee, as someone mentioned earlier although this may be irrelevant, as they still own the place)
Therefore, I'm not sure if I entered a 'contract' as such, by walking on it!

I've finally had a reply from them though, via email, so If my client chooses these two photos in question I'll get in touch with them for 'permission' or have discussions.