Did Peter do Lydiard training for all of his career is an interesting question. There was a time, maybe in 1963, when he and Arthur had a falling out. One of the reasons for this, Peter told me. was that Arthur had gotten Peter training with one of his, Arthur's, lesser known runners, a guy called Don McFahrquahr who Peter described as "a Lydiard athlete but also a free thinker who later became a coach." Apparently one way DM's free thinking (I'm not going to try to spell his last name again) showed itself was believing that the key to the Lydiard system was "the conditioning phase" (base phase) "and once you've done it you don't need to put much time or effort into other kinds of training."
Peter told me that he was doing most of his running with DM and it was creating tension between Arthur, Arthur's other guys, and himself and he got a lot of questions about whether he was still one Arthur's guys or not. So he had this period when he wasn't doing what Arthur would have had him do but was he still doing Lydiard training given that he was running with someone who was himself a Lydiard athlete? Anyway, he and Arthur reconciled, it was the only time Arthur ever took back a runner who had left him in time for the '64 Olympics and stayed together until Peter retired in 1965.
The second question has a much easier answer. Peter told me if he was doing it over it would be the same except that in the base phase he'd have had one day a week where he'd have done a session of "easy" 300 or 400 meter intervals and not "been purely a distance runner."