Never heard of them.
I haven’t either; apparently, they’re based in the U.K., and if the MH-17/SA-11 report is any indication, Bellingcat is very proficient at open source intelligence (OSINT) analysis. Lots of details in that report, down to the “skirt” numbers on some of the individual missile launchers.
Which begs another question: most mil bloggers don’t have the time to pour through literally hundreds of images, then validate and geo-locate them, and build the narrative. Makes you wonder who is really behind Bellingcat, or who is steering them in the right direction. I would guess the organization has close ties to the Ukrainian intelligence services and possibly some of the western agencies as well.
garbage in..garbage out