Can someone explain his career trajectory? Before 2017, he looked like he had a great future. He won the British Championship three years in row, in 2014/15/16. Since then, he's finished 5/4/4 at Nationals. He hasn't done any better internationally. He's been competitive in lower tier races, but not in the big leagues. His highest finish in the DL is the 4th at Monaco this year. and except for his 3:30 in that race, he's only run 3:34 since 2016. Ditto for international championships.
What happened? Why hasn't he delivered on the promise of those early years? It doesn't look like he got pushed aside by a new generation of British runners. Was he injured? Or did he just reach his peak early?