Corner of white red, where the building is clad...
Standing at that corner, the main bedroom window was. Visible to WPC Jeapes. Furthermore, at the position she was stood facing the house, she could see the front door and the dining room window..,
That angle allowed her to see the rifle leaning against the right hand side of the main bedroom window, nothing could be any clearer...
According to Jeapes she was standing at a shed. She said said she took over at the containment position used by Collins, Delgado and Alexander-Smart. They were on the kitchen side 30 meters from the house by the shed.
Here is this shed they were near so that if necessary they could jump behind it for cover to protect themselves:

They were observing the kitchen side of the property. They could not see in the master bedroom window.
Given the distance from the house they could not see in any of the upper floor windows. At best they would be able to see something that is right against the window they would have no depth perception. She thought she saw something leaning against the boxroom window which was like a skinny stick so thought it might a rifle barrel. A broom would look the same as a rifle barrel because all she could see is what appeared to be a skinny thing sticking up. She couldn't see the lower portion of whatever she saw only the top portion. Whatever it was never moved, it was still there when the raid team found the bodies.
If it had been the murder weapon that would have been even ore proof that Sheila was murdered because after she was dead she couldn't have taken the gun and walked it to the boxroom window nor could she have walked it to the master bedroom window for that matter.
So on top of making things up you are making up things that if true would be even more evidence Sheila didn't commit suicide. Gee I wonder why Jeremy doesn't want your help...