When John is "confessing" to Fr. McCready, the good father tells Jhon that the unborn child of the suicide had a mortal sin on its soul and that that sin was of the child's father. That is clearly contrary to the teachings of the Catholic Church. The sin that would have been relevant was Original Sin, and Original Sin is the result of the sin of Adam.
Instead of a period handrail, there is a red rope which is used by visitors to Knebworth House in the modern day.