I haven't claimed NB was shot coming up the main stairs. I believe NB sustained the two facial shots whilst situated on the landing steps facing the entrance to the main bedroom door with the perp and ejection port of rifle just within the entrance of the main bedroom.
This fits with the:
- trajectory of shots, 20 degrees below the horizontal: NB slightly lower than perp.
You are contradicting yourself. The landing is not a step it is the hallway floor which is the same exact height as the bedroom floor. Your drawing featured Nevill being shot on the steps not in the hall.
Nevill being shot while standing outside the bedroom door would not enable someone shorter than him to shoot him in the face at a downward angle unless the shooter was standing on something. Moreover, the shooter was positioned between 9:30 and 10:30 while shooting Nevill in the face. No shooter could accomplish such from right inside the door they would have to be near the corner of the room.
The red shows the bullet trajectory in order to shoot the person entering. The yellow shows the trajectory of the casings. Standing in such location would not enable to killer to fire at Nevill at a downward angle.
I believe NB then turned and fled down the main staircase with the perp behind him. At this point he sustained the shoulder and elbow shots.
For the 100th time, Nevill's graze wound and the shot to his shoulder were not fired at his back. The killer was at 8 O'clock to 8:45 when the shoulder shot and graze wounds were delivered. It is totally impossible for someone standing in the 6 O'clock position to achieve such trajectories.
A 3 dimensional image would show the trajectories much better because all angles can be shown but it is what it is:

Apart from the angle being impossible to achieve, if the bullet that grazed Nevill had been fired while he was on the stairs then such bullet would have been on the stairs or at the bottom of the stairs not inside the bedroom.
You totally ignored the evidence and simply made up that he was shot entering the bedroom and on the stairs because you want to pretend that Nevill called Jeremy while Sheila went upstairs and shot June then he heard the shots and ran upstairs to check things out. You made such up without regard to the evidence and are now trying to find ways to distort to pretend evidence supports this made up account. The evidence doesn't support it whatsoever. The trajectories can't be achieved you claims are impossible.
- casings ejecting slightly forward and to the right although flight could be impeded by any objects eg right angle of main bedroom walls. I believe casings DRH/3 and DRH/4 pertain to the facial shots and casings DRH/13 and DRH/14 pertain to the shoulder and elbow shots.
Firing down the stairs would result in the casings being ejected to the bottom stairs or even ending up on the ground floor. Your suggestion that DRH/13 would eject not down the stairs to the right but rather directly to the left of the weapon is patently absurd. DRH/14 is on the wrong side of the landing and we know it is from the kitchen. One casing from the kitchen was missing and this was the only casing that was out of place so has to be that casing.
DRH/3 and 4 deflecting forward left off the wall (the wall that is directly to the right of the doorway) would result in them landing near June's side of the bed. The trajectories of the bullets don't fit nor does the locaiton of the casings your suggestions are not the least bit possible.
- none of NB's blood was found in the bedroom. Two small blood stains were found on the landing although it's unclear whose blood it was. AE's WS states EP washed and removed blood staining from the carpet on the stairs. No mention of blood staining on hall carpet. A light distribution of blood staining was found on the kitchen floor leading to where NB was found. It seems there was a trail of blood from the landing leading to where NB was found:
Two blood stained carpet samples were taken from the landing DRH/47 and DRH/49.
http://miscarriageofjustice.co/index.php?action=dlattach;topic=165.0;attach=221
According to AE's WS EP pointed out some blood on the stairs:
http://miscarriageofjustice.co/index.php?action=dlattach;topic=1053.0;attach=3100
There was also a "light distribution" on the kitchen floor:
http://miscarriageofjustice.co/index.php?action=dlattach;topic=165.0;attach=216;image
http://miscarriageofjustice.co/index.php?action=dlattach;topic=165.0;attach=217
I will endeavour to get a 3d computer animated model drawn up in the near future, copyrighted of course
Noone is getting their grubby paws on my intellectual property 
Why didn't JB's useless defence (yes that's you Paul Terzeon and Geoffrey Rivlin) get to grips with all of this pre trial?
You are making things up and your made up things could not be used by the defense. There wasn't a trail of blood on the stairs. They found the 2 static drops in the hall that they took and tested. DRH/49 was group O while DRH/47 was inconclusive. DRH/49 got there either by Nevill walking to Sheila's room and then turning around and running downstairs instead or it dripped off the killer/weapon after the Kitchen episode when the killer went to get Sheila.
You are so biased that time after time after time you IGNORE that they didn't test the blood stained bedding NOR did they take all the blood from the bedroom carpet they only took 2 swatches leaving the rest of the blood stained carpet. They only tested 5 stains on each swatch not all of them thus there is no way to know if the other blood on the swatches that went untested was Nevill's. Nor is there anyway to know if Nevill's blood was on the bedding since it was not testing. Nor is there any way to know if the blood stained carpet that remained had any of Nevill's blood since it was not tested. When you insist that Nevill's blood definitely wasn't in the bedroom that is a false claim. There was a considerable amount of blood that went untested int he bedroom. The defense had no ability to say Neivll's blood definitely wasn't int he bedroom since there was untested blood that could have been his.
Moreover, the defense had no experts who would opine that Nevill had to bleed profusely on the bed or carpet. His clothing soaked up the blood from his shoulder wound, his graze wound did not cause any bleeding. His lip and jaw wounds caused mainly internal bleeding, the external bleeding dripped on him mainly. There was no way to say that there would have to be much blood in the bedroom and no way to establish for sure his blood wasn't in there.
Testing 5 drops from a swatch with 20 proves who those 5 drops belong to it doesn't prove who the 15 untested drops belong to. it can be used to establish the person the 5 belonged to was standing over the swatch it can't prove that no one else was standing there as well. You always hold out evidence as proving things it doesn't.
You don't follow the evidence where it leads. You make up what you want to believe then strain to try to make the evidence fit.
This has a simplistic legend which shows the position of the shooter and Nevill as well as the trajectory of the casings in yellow. This is the horizontal angle of the face wounds. You simply superimpose this anywhere in the house you want and it will show where the killer would have to be to shoot Nevill if he were in such location. What this fails to show is the vertical angle this is just the horizontal. The vertical angle was downward which means the killer was at a higher level than Neville or Nevill was not fully upright when shot. You have to account for both the vertical and horizontal.

This shows the angle of the other 2 shots and in fact the angle is probably closer to the 9 "Oclock position than this, this is the furthest exten from 9 tha tis possible:

With respect to the vertical angle the shoulder shot again Nevill was not fully upright or the killer was higher. The graze wound is low enough that it is possible to inflict while Nevill and the killer are both on the same level both fully upright even if the killer were shorter.
Your claims hold no water that is why the defense didn't make such claims at trial.