Ok this is from a 2002 appellate decision. [2002] EWCA Crim 2912 Case No: 20011745 S1
This is where I got the part about the gun being left on the kitchen table I knew I read it somewhere:
"Having walked to the house from the lane there was further conversation. The appellant told the police that Sheila Caffell could use a gun. He said they had gone target shooting together and she had used all the guns in the house before. In the light of what they were told the uniformed officers requested armed assistance before any attempt to search the house was made. The appellant dictated a list of the firearms kept at the house. He told the police that he had loaded the .22 automatic rifle the previous night because he thought he had heard rabbits outside. He said he had left the gun on the kitchen table with a full magazine and a box of ammunition nearby. Those who saw the appellant at the scene at that time described him as remarkably calm. At some stage during their conversations that morning PC Myall and the appellant spoke about motor cars. The appellant said that the Osea Road Caravan Site company, "would be able to stand him a Porsche" car at some point during the year."
Aaah, I see now... looking at the kitchen crime scene photo, the table was set for the following morning's breakfast so as you noted earlier if the rifle was left on the table it would have been removed by June or Nevill. If JB did later change his story... big mistake, he should have stuck to the more believable 'settle' one.
Could also have been a misinterpretation by the author(s) of that 2002 decision document of what JB actually said .
He told David Boutflour shortly after the murders that he left the magazine in the rifle, whereas in a later police interview that he removed it.
Same with fictional shooting rabbits tale... imo just gave him the opportunity to test fire the rifle, fill the magazine and make sure that it was working OK for his plan later that night, then told the police he left it out to give the impression that Sheila had easy access to it.
"oh what a tangled web we weave when first we practice to deceive"