On a video (Taz, Murky?), there a zoom in on the box immediately to the right of a footman. It say's "Her Majesty".

She's wearing a coat, which she wouldn't have been wearing indoors at the engagement. I'm linking to the description provided by the blog What Meghan Wore of two engagements held at BP.

Permission to take photographs may have been given to the organizations or given to H&M but the permission was limited to the location where the meeting was held and for the duration of the meeting.