fwiw, I've known about brochs for decades, since the 80s - thanks to Katharine Kerr, an excellent old guard fantasy author, who uses ancient Britain as inspiration for her Deverry series (which is excellent classic fantasy).
Brochs figure prominently. She does excellent research and they were communal living spaces and centers of leadership in her books, which is what current thought (at the time) believed them to be in use for.
I've visited a couple in Scotland. Iron Age Britain is probably my most favorite time period and landscape after the pre-pottery Neolithic.
*coughs in huge nerd* sorry