This is arguably the standout episode of series 7, if I'm honest I guessed the villain before the crime had even been committed, but it was the combination of writing, execution, narrative and character play that made this such a terrific watch.
The appearance of former Detective, Sullivan that was the highlight, I was very sad when he left, and it was great to see he hadn't changed, still smart, authoritative, dependable and handsome, if took me a long time to take to Jack Dean's slightly abrasive Detective, but he has grown on me a lot, I thought he was excellent here, a terrific scene where he spoke fondly over his injured colleague.
It worked well as a mystery, featured some very familiar faces, but it was the dynamic between Father Brown and Sullivan that made it extra special.
A great episode. 9/10