Yes he has - for starters he has changed the time of phone calls to fit in one from Nevill. The phone calls for me don't add up and the fact that his story has changed looks very bad on him. If Jeremy can prove the phone calls happened, he'd be out, but having already shifted the times - who can possibly take him seriously?
Times of phone calls from others like Mugford, her flatmates and even the police with their mysterious slow clock that changed times as will are conveniently forgotten in the zealous quest of some to stress the guilt of Bamber. I'm not so sure that I myself would have been able to give exact times of phone calls from various people?
In fact I can tell you that as a fact. When my stepfather died it was a time of utter confusion with one saying this and another saying that and I certainly could not even to this day give you the times certain things happen.
Then people think Bamber to have some kind of super memory. If he was guilty then to my mind the times would have bean the first thing he would have thought of. In fact his very confusion about the matter indicates to me at least that these are the recollections of an innocent man.