Yes, a temporary period of unconsciousness for Nevill supports a Sheila scenario more than a Jeremy scenario. It may have coincided with June and/or the twins being attacked.
So what led to the unconsciousness, being shot 4 times? Having his head smashed in - enough to crack his skull? When did that happen? Before or after he called Jeremy? If before, how did he manage to dial the number and talk to Jeremy? At that point wouldn't a 999 call be his best bet? If he had managed to dial 999 (as some believe) why ring Jeremy at all? If it happened after, that means his murder happened while Jeremy et al were outside and no one heard anything - including Jeremy.
Yes, it might fit a Sheila scenario, which is why it just doesn't work. All very desperate.