Or back up what she said she said.
Correct.
If Bamber rang to 'hear a friendly voice', the call would be over one minute. Perhaps several minutes.
Bamber would need to explain what had happened, how he feels and why he has rang her at 3am. There is also a strong chance Julie would attempt to assist him. At least Bamber thought that would happen.
Bamber just giving an information statement and Julie just saying 'go back to bed' will take one minute or less.
Flatmates confirming Julie was on the phone for only a minute or less, confirms her WS. Bamber did not phone for advice.
It is not surprising Bamber has kept so quiet on this. He really has made 'no comment' since 1985.