Cast. Back to Series Midsomer Murders, Series 15 (Sets 23 - 24): The Sicilian Defence. Episode cast overview, first billed only: Neil Dudgeon ... DCI John Barnaby: Jason Hughes ... DS Ben Jones: Fiona Dolman ... Sarah Barnaby: Tamzin Malleson ... Kate Wilding: Richard Lumsden ... David Farmer Jo Woodcock ... Harriet Farmer Starring: Neil Dudgeon. ... DCI John Barnaby. Cast (in credits order) complete, awaiting verification. Jason Hughes. Schooled in Murder US TV RATING: TV-14. ... DS Ben Jones. Could the attack which left Harriet for dead a year ago be linked to moves on a chess board? Neil Dudgeon. Soon afterwards, a serial killer strikes members of a chess club. Fiona Dolman. More Episodes. The Sicilian Defence Series 15 (Sets 23 - 24): Episode 5. And where is her boyfriend Finn? Harriet Farmer wakes up after being in a coma since the night she tried to elope.