Suggestions by @spectritus

Peter Davison

as Man who comes to talk in Frankenstein

Score: +1

Peter Davison

as Man who delivers the letter in Dracula

Score: +1

Benedict Cumberbatch

as Sagramore in Merlin

Score: +1

Michael Sheen

as Dagonet in Merlin

Score: +1

Chiwetel Ejiofor

as Percival in Merlin

Score: +1

David Tennant

as Lucan in Merlin

Score: +1

Ewan McGregor

as Bedivere in Merlin

Score: +1

Henry Cavill

as Lancelot in Merlin

Score: +1

Yasmin Finney

as Unnamed character in Merlin

Score: +1

James McAvoy

as King Arthur in Merlin

Score: +1

Emma Thompson

as Morgana Le Fay in Merlin

Score: +1

Liam Cunningham

as Merlin in Merlin

Score: +1

Mandip Gill

as Unnamed Character in James Bond

Score: +1

Freema Agyeman

as Miss Moneypenny in James Bond

Score: +1

Jack Whitehall

as Q in James Bond

Score: +1

Liam Cunningham

as M in James Bond

Score: +1

Matthew Lewis

as Lucas Henderson in Chesterton

Score: +1

Bonnie Wright

as Molly Avery (née Damford) in Chesterton

Score: +1

Murray Gold

as Composer in Sherlock Holmes

Score: +1

Nicole Kidman

as Poison Ivy in Batman

Score: -2