They were slightly late coming in the church to sit down.
You can see & feel the tension between these two ladies. MM is blinking a lot, I can feel how out of place she is, she is out of her league with the big political players in this church. Her insecurity as not good enough is apparent, that’s the feeling I pick up.
When Harry sits back down after his speech, she goes back into smug mode.
MM entered a church with shoulders bare showing her disrespect for traditions of the British people and religion as a whole.