2004 started promisingly for Fenn with an 800m bronze medal at the World Indoor Championships in Budapest, Hungary. She also broke the 1000 m British Record before Kelly Holmes retained it later that same year. In the 800m at the 2004 Summer Olympics in Athens, Greece, where Fenn accompanied teammate and eventual gold medalist Kelly Holmes, she progressed through the first round but in the third of three semi-finals found the pace too fast and finished fifth therefore not qualifying for the final.