Complex sentence: Since leaving Johnny Hate Jazz, Thornalley has worked primarily as songwriter and record producer for other artists, including Bryan Adams, Melanie C, Ronan Keating, BBMak, and Pixie Lott.
Split into simpler sentences: Since leaving Johnny Hate Jazz, Thornalley has worked primarily as songwriter and record producer for other artists. Other artists Thornalley has worked with include Bryan Adams, Melanie C, Ronan Keating, BBMak, and Pixie Lott.