The only reason it is known that June walked about a short distance while Sheila was up, was because June's blood was in the bedroom. After she had been shot 5 times in bed.
Only Nevill could have given Sheila injuries, but he would have just used his 8 stone weight & 9 inch height advantage to smother her instead.
Bamber didn't need to injure Sheila as she was zonked out, half asleep & not strong enough to put up any resistance.
The expert evidence says Sheila had no injuries. Which matches the photos.
Everything fits.