If the call from Neville was fake to provide an alibi it was planned - so what are your ideas for why in his plan -
Indeed it was part of his plan all along to present the alibi that he received a call, he even told Julie about such being part of his plan prior to the murders and she in turn testified to such and included it in her statements.
he claimed to have called his father back a couple of times ?
Why is this surprising? He wanted them to believe the call got cut off midstream thus pretended he called back to try to clarify things. Calling back is something one would be apt to do under the circumstances.
Why if he was trying to create a siege situation ( as claimed ) did he not mention a shot being fired .
Claiming to hear shots fired would give the police reason to go in right away.
Subsequently he told certain people he thinks he heard a scuffle taking place or shot fired before the phone went dead. It is rather obvious why he didn't say that at trial though. Saying he heard shots would mean he should have called police instantly. He admitted he didn't call police instantly he testified that at first he didn't think it was an urgent situation and that only after thinking about it a while did he realize it was urgent. Saying he heard a shot fired certainly would not jive with this testimony.
Why did he "make up" a story about looking through a phone book ?
He didn't make it up he actually did look through the phone book. Whether he did so in order to try to slow down police response or did so by accident because 999 would occur to someone who is in an emergency situation but he was not actually in an emergency situation so he had a brain fart and didn't think of 999 is anyone's guess.
Why did he not make sure he knew the times of the calls?
That would look pretty bad if he wrote down on a piece of paper the time he made up receiving a call from Nevill, the time he called police and a fictional time he called Julie. No one would do such a thing. Particularly since he knew police could not get the times from the phone company so he was free to make up whatever he desired.
Why did he get in a muddle about whether he called Julie before the police ? If Julie was part of the alibi you think he would have got the order and the times right?
He had his lies straight at first- he was consistent in his claim that he called Julie after police. A month later he was interviewed 4 days in a row. On his first day he forgot and accidentally told the truth when he was interviewed by Taff Jones. When DS Jones interviewed him he prepped himself more and reverted to his prior lie. Then Jones nailed him and he said he wanted to see what he wrote in his statement. He wanted to read his statement in order to refresh his memory of his lies but Jones refused to show him. So he simply stated he could no longer remember and deferred to what he put in his statement.
Why did he think the police would be able to trace the call?
Obviously he didn't. If he knew they could trace the time of calls then lying about calling Julie afterwards would be pointless. His lying demonstrates he didn't think they could get a written record proving the times of any calls. He told police he thought they could tell just to try to fool them into thinking he didn't realize they would not be able to tell if a call had been made or not because if he knew then it would be easy to make the call up.
In fact that is why he wanted police to pick him up . He wanted them to see he was at his house. Since they wouldn't he made sure they arrived first. Since phone records proved useless they could think he called police from WHF then walked outside and waited for police and just pretend he called from his place and drove there after calling.