Complex sentence: In July 2010, Motion returned Kingston-upon-Hull for the annual "Humber Mouth" literature festival and taking part in the Larkin 25 festival commemorating the 25th anniversary of Philip Larkin's death.
Split into simpler sentences: In July 2010, Motion returned Kingston-upon-Hull to participate in the annual "Humber Mouth" literature festival. He took part in the Larkin 25 festival commemorating the 25th anniversary of Philip Larkin's death.