I think overall you did a very good job.
There were a few things that could be improved in my opion, but I am very much a beginner so I only offer the following as things that occured to me a viewer who happens to have an interest in video. Don't hold to much store by what I say!
On 20 seconds - the video cut to Jamie leaning over the ring, then cut to him squaring up to a punchbag before quickly returning to him talking. It seemed to me like the double cut-away happened to qucikly and didn;t really add anything to the story. Maybe one cut-away that lasted longer would have worked better?
On 0:41s the video cut from one talking head to another and the background sound was significantly different. Jamie's head was also in a slightly different position, or the camera was, which made it obvious that it was filmed at a different time.
It might have worked better if the second part of the interview kicked in over the top of him training, and then the video could cut to him a few seconds down the line so the audio from him talking could have been mixed with him punching a bag or whatever.
Good job overal though! What mic did you use out of interest?