I set my half pb at Peterborough in 2012 and I really am incredibly smug about my pacing that day. It is (so far) my best race by quite a way and I was redlining nearly the whole way. First mile split 5:18, slowest mile 5:27, fastest mile 5:16, average mile pace 5:19.
I think his 4:30 first mile is just one big wind up anyway and he actually has slightly more brains than that, not to mention beliefe. I do think he will be capable of something sub 75 and will deliver on it, despite the lack of info we have. Just a hunch. I would guess he'll end up with a 74:26.
Best of luck to everyone else racing, hope you have a good one.