If you’re referring specifically to the clips from the funeral, I strongly suspect it was WHs, as directed by MI, done with military precision and advanced surveillance equipment. These weren’t casual, let’s-film-the-funeral-for-posterity recordings; they were precisely-placed, precisely-timed and precisely-orchestrated surveillance units that are part of the overall plan to trap the beasts.

Edit: Might I add… a most amazing, impressive and brilliant plan, IMHO.