I asked him who he called first after the 'supposed' call from Nevill and he said 'the police' - that's all I asked him about the calls.
Given that this is a key issue, why is that all? It seems that you caused him to focus on a single issue, without considering the closely related issues. For example, it presumably didn't seem important on 7th August 1985 to "fill in" the time line, so that there would be some mention of what he did between 3:10am and 3:25am. If that's the case, he had little reason to suppose in hindsight (including now) that what was in his first statement should be regarded as correct in every detail, or even approximately correct, especially the "implausible" details, such as his use of the word "immediately".