Fassett with two 't's.
I thought of going for that today but it felt a bit like shooting fish in a barrel (not that I'd shoot any fish outside of barrels), and I always like to leave them if a new tagger shows interest. But fair game, of course.
I was actually surprised we hadn't had this yet. I tagged the German Hospital a while back (which oat44 refers to in his clues), but apparently not the square itself. I think at the time I thought it would be too obvious.