Ann Eaton is not a credible witness.
Agreed, but even if her assertion about Jeremy were correct, it doesn't imply the Jeremy's telephone call to Pc West took 11 minutes. Even the prosecution accepted Pc West's assertions at trial that he dealt with Jeremy's call quickly, but they suggested his written note of the time when Jeremy rang him was a mistake. The mistake wasn't attributed to an incorrect clock, as the clock had been checked later and found to be working correctly.
Pc West noted that car CA7 was "at scene" at 03:50, which was in rough agreement with Bonnett's note of 03:48 as the arrival time of the same car, but these times are too late to fit with any guilty scenario unless the police response was incredibly slow, which isn't what the prosecution suggested.