No, she's a Judge. A Magistrate is a lay person as you say, but she's a district judge. It's just that the particular kind of judge she is has the word "Magistrate" in the full title.

She is (or was at the last time they updated their lists) a "District Judge (Magistrates' Courts)" which means ordinarily (this case is anything but ordinary) she would not be assigned to a Crown Court but would work alongside Magistrates in their court. Unlike them she can sit on her own (as she does here) deciding things for herself.