I don't think he could or did run a 30:47 10k. And I'm not sure that the editing of his Wiki page to change that to a 7k was done by him. Someone on this board discovered a triathlon split of 30:47 for 7k, but don't know that it was ever confirmed that the 7k was the source of the 10k PR.
I think it was mentioned that it was the Cambridge Duathlon, which if true, then the split was probably 7.5K, not 7K... not that either are any where close to 10K that he claims on his website (red down arrow at top).
And technically, we don't know for sure that's where the dubious "30:47" came from. But it appeared to be an intriguing coincidence of identical times that seemed to explain the claim.