my thoughts on timings in general are this
in those days - the police were well aware of the importance of timings and reliable clocks. The period of time we are talking about their Notes and time keeping was vital for evidence . they did not have technology to rely on . So IMO any changes or stating that clocks were wrong is either deceitful or down right sloppy. In court they would be expected to be accurate and detailed with their evidence.
However members of the public would obviously be more lax with their memory or accuracy . The argument that Jeremy would remember in detail all the timings and what was said because of the horrendous outcome is quite frankly ridiculous ( IMO so not to cause offence) Firstly when he took the call if he is innocent he did not know what the outcome would be and then he would ( as reported ) be in total shock . And his first thoughts would not have been I am shortly going to have to make a full and detailed statement . And if he made both calls to prove his innocence he would have pushed to mention the other call . As far as I am aware he mentioned about his fathers phone being engaged when he tried to call back that was all ?
At the point when Jeremy phones, West didn't know what the outcome would be either and at around 03:30, he was probably bored and low on concentration or as you say - 'sloppy'. He was criticised for being just that after given evidence. One thing he would remember, is taking two calls, one from Nevill and one from Jeremy.
My dad had a massive heart attack in front of me I had to call the emergency services - I was in total shock but the time of the call was 21:25 - it's etched on my brain. It took 12 minutes for the paramedics to arrive from me hanging up the phone (seemed like a lifetime), he was pronounced dead at 21:40. The undertaker arrived at 10:10. Like I said, the times are etched and Bamber supposedly didn't even know there was much wrong when he made his call. He recalled the times perfectly the following day without any problem. After he had time to think, he realised that calling Julie first, was a problem.
Years later he made a complaint against West, claiming her perjured himself by changing the time on the log from 03:26 (the time Jeremy clung to at trial) to 03:36. Now he argues the opposite. He required the time to be 03:26 at trial so he could argue he called Julie after the police - he needs the time to be 03:36 now, so he can argue that Nevill called. So when did he called Julie?