Suggestions by @cosmolover

Lyndsey Marshal

as Nurse Booth in Strong Poison

Score: -1

Stephen Moyer

as Gerald Wimsey, 16th Duke of Denver in Strong Poison

Score: -2

Jack Davenport

as Charles Parker in Strong Poison

Score: 0

Craig Parkinson

as Norman Urquhart in Strong Poison

Score: +1

Perry Fitzgerald

as Philip Boyes in Strong Poison

Score: -1

Harold Perrineau

as Philip Boyes in Strong Poison

Score: -1

Kate Phillips

as Lady Mary Wimsey in Strong Poison

Score: +3

Joseph Kloska

as Mervyn Bunter in Strong Poison

Score: -1

Emerald Fennell

as Helen Wimsey in Strong Poison

Score: +1

Emily Watson

as Joan Murchison in Strong Poison

Score: +3

Rachel Hurd-Wood

as Lady Mary Wimsey in Strong Poison

Score: +1

Felicity Jones

as Lady Mary Wimsey in Strong Poison

Score: +2

Adrian Lester

as Charles Parker in Strong Poison

Score: -1

Jessica Raine

as Lady Mary Wimsey in Strong Poison

Score: +1

Pam Ferris

as Miss Climpson in Strong Poison

Score: +1

Francesca Annis

as Cremorna Garden in Strong Poison

Score: +2

Brenda Blethyn

as Miss Climpson in Strong Poison

Score: +2

Claire Foy

as Harriet Vane in Strong Poison

Score: -1

Josh O'Connor

as Hon. Freddy Arbuthnot in Strong Poison

Score: +1