Main Characters Dr. Katie Roden 16 main appearances Trudi Malloy 16 main appearances Siobhan 16 main appearances Jessica 16 main appearances Richard Dunlop 16 main appearances Dominic 16 main appearances Hari 12 main appearances Mark 10 main appearances Jack Hudson 6 main appearances Dan 6 main appearances Lucas 6 main appearances Tom 6 main appearances Chris Webb 4 main appearances Jeff 3 main appearances