For anyone to suggest that these videos of the crime scene do not/did not exist, and that images of Sheila are/were not contained within them, would be very misleading because clearly such video footage does, and did exist, and still to this day exists, so do not doubt the authenticity of the still image taken from one of the video tapes of the crime scene which was taken by police during the training exercise...
I'm not particularly bothered how a still image of Sheila's body showing all this additional blood got to be around Sheila's mouth, face and on her neck fell into the hands of TV Documentary makers, the fact is that it did, in the same way that other authentic images taken from crime scene pictures taken by the police were also part of the same documentary...
These pictures and images were included in the documentary to give it a sense of realism, and were in fact snippets of the real thing mixed in with mocked scene images, so do not be fooled by anyone suggesting that the so called grainy image of Sheila with all this additional blood around her mouth, face and neck is not a genuine one. Furthermore, the documentary makers managed to get hold of other genuine images taken by the police at the scene that morning, and one or more of these were also shown on the documentary in question, so it is without question or doubt that the TV Documentary makers did get access to authentic images from the police files or records, and it is not for me to have to explain how they managed that...