Hounslow won nine medals at the ICF Canoe Slalom World Championships with a gold (C2: 2013), a silver (K1 team: 2009) and seven bronzes (C2: 2010; C2 team: 2009, 2011, 2013, 2015; K1 team: 2014, 2015). He also won 9 medals at the European Championships (2 golds, 3 silvers and 4 bronzes).