Just had a quick read of this statement and that of Rozga, and found just a small snippet that surely would have been picked up if this statement was that of PC Webb.
Near to the start he states that the team were informed that Jeremy had taught Shiela how to use the .22 rifle, which would surely put to bed the claims that shiela could not or did not know how to use a gun. obviosly along with the fact she was a farmers daughter post gun laws.