For Bamber to have staged the call from WHF he has to have an answer machine switched on. Otherwise the call would not be answered and therefor not logged with exchange.
If he just claimed Nevill called him he was running the risk that the Police could check with the telephone exchange as to whether any such call was made.
On the thread starter point I believe it would be almost impossible for Sheila to come through the massacre relatively unscathed. Which is the point Adam was making.
Nevill putting up such a fight for his life was not part of the plan. JB most probably thought he could finish off Nevill reasonably quickly.
For someone who was head of a family, farm, businesses, the family fortunes, courts, & a former RAF pilot, Nevill showed great weakness with Sheila.
Ringing someone's AM he employed as a farm labourer. Together with other huge mistakes which are in the thread post.