Simple facts

There was no motive.
Even at the original trial the prosecution could not suggest any motive — apart from an inexplicable rage, of which no evidence has ever been offered.
There was no time.
In the space of 3 minutes, at most, Siôn Jenkins, suddenly consumed by rage, would have had to leave the house and go round to the back to pick up the tent peg lying on the coal bunker — even though there were other tools much nearer to hand. He would then have returned to the patio to commit the brutal and bloody murder involving a minimum of 10 blows to the skull. (The murder, it now transpires,also included the bizarre act of forcefully pushing a piece of plastic bag up Billie-Jo’s nostril, using an object of some kind. This did not emerge at the original trial.) Having done this — without getting any visible blood on his jacket — he would then have cleaned himself up and completed the transformation from enraged homicidal maniac to his normal demeanour. Police at the time repeatedly stressed that the murderer would have been covered in blood and probably paint too. Somehow this vital detail ceased to matter once Siôn Jenkins was charged.
There was no noise.

It is hard to imagine how such a brutal act could have been committed without his two childen, who were nearby, being aware that anything unusual was taking place.

It was stated at appeal that it was implausible that an intruder could have approached the house unobserved, entered through the side gate and carried out a motiveless attack.There would not have been time for this to happen.

Really?

In point of fact, the time available for that to happen would have been five or six times greater than the time in which Siôn Jenkins is alleged to have committed the murder.

What is more, the open side gate adds weight to this hypothesis. An intruder would have gone right past the coal bunker where the tent peg was lying.

Finally, there is evidence of someone in great distress running along the alleyway at the back of the garden at around the time of the murder.

Which of these two scenarios sounds more implausible?