The hanging scene depicts coiled nooses, which are an American invention. In that era the British used simple slip knot nooses for executions.
At approximately 25 minutes when the victim's body is being carted to the white farmhouse, a telegraph pole and phone wires are clearly visible to the left of the building. There is also a television aerial on the left-hand chimney stack.
When Morse and Adele go the graveyard in Ireland and have the grave opened, a 150 year old grave at that, the coffin is still in excellent shape despite being in the wet Irish soil for over a 150 years. It should have been rotten and crumbling. Also the bags holding the stones that were in coffin are still in pristine shape. They were not rotted after being in humid conditions in the aforementioned damp Irish soil.