No Caroline there's a gap of 20 minutes which Jeremy has to explain(it happened in the David Bain case too). He stated he had flicked through Yellow Pages trying to find the Chelmsford Police Station number when any rational person faced with an emergency such as that would have immediately dialled 999,as would Nevill in reality.
That's what I'm saying - he'd have certainly had that part of the plan worked out and calling 999 would (IMO) have been part of it. Think about it - if he's innocent, he didn't know it was an emergency - only that Sheila had the gun. Not that she was threatening anyone, just that she 'had the gun'. The Bambers were private people, didn't like people knowing their business. So he gets the call and not sure what to do, he calls Julie - she is neither use nor ornament and tells him to go to bed. Rather than make a fuss and call 999, he decides he will call the police but not on the emergency number. If he was guilty, he knows they're all dead and so calling 999 would make more sense. If he was that 'phone call savy' he wouldn't have called Julie. But according to you, he called his number from WHF, cycled back to Goldhanger, had a wash, then changed, called Julie, looked for two different phone numbers - all in 20 minutes?
