Sorry for the confusion QC, I could have worded that better, I know you didn't mean they had bent down and picked them up with their hands, here:
To explain the casings you now have experienced SOCO's or TFG unwittingly picking up casings on the soles of their boots and all four of them get walked upstairs and deposited again in the bedroom.No officers trained to be observant in a crime scene notice that they are disappearing/reappearing . None dislodge from the boots ?on the stairs or in any other rooms and the casings in the boys room remain undisturbed, (perhaps they were more careful in there) - why didn't the clumsy oafs walk in the blood too? Sorry but I'm not buying it, it was the SIO that was unprofessional with his assumptions, the rest made some mistakes but knew enough to be careful in a crime scene.
Here's a thought though, why not have JB move some of the casings to make it look like Nevill went to June's aid?
I do agree that if NB doesn't go upstairs it solves some minor problems but in doing so, you create new ones that require just as much head scratching and supposition.
Adam's scenario is essentially the one the police believed the most likely but to save arguing about the unknowable, how about I just put your theory in the maybe pile along with all the others. 
I have not created a new problem. I've not pulled something out of a Bizarro parallel dimension. All I have done is given you a very ordinary, down-to-earth resolution for problems in the evidence.
First, you mention nothing about the idea that the casings could have been ejected out on to the landing when fired. This would explain it all. The casings are tiny. They could then easily end up moved, kicked around and so on, especially towards the main bedroom, which was a focal point for officers. If you doubt this phenomenon in general, then tell us where the missing cartridge case is from the kitchen. Clearly it has been moved somewhere, I would say probably by accident. The casings are important to the crime evidence, obviously, and their position should be taken account of. I don't say we should ignore where they are found, I only say that we should not rely on where they are found, as that's only where they are found at a particular point, so it would be foolish to do so.
You ask why didn't the "clumsy oafs" (your expression) walk in the blood. My answer is that they undoubtedly did. They had no choice. They weren't clumsy oafs at all. They had arrived at a potential armed hostage situation and they had go in and find Sheila and rescue or locate the others.
You ask why the casings were not dislodged on the stairs or elsewhere, but I did not say anything to the contrary. As just mentioned, they may have been ejected out on to the landing from the rifle, when fired. It is also possible that at least one casing was collected in the treads of somebody's boot, either on the landing or earlier along the footfall flow between the kitchen and the main bedroom, where officers would have stopped to examine the two bodies.
I do not say that this means the officers were unprofessional or incompetent. They may have been in other respects and I may advance that view, but my post about the casings doesn't rest on this. I simply state as a cool matter of fact that evidence would inevitably have been compromised at the scene as a result of the police operation, and this would have been next-to-unavoidable.
I strongly doubt Jeremy would be messing around picking casings up.
