But I distinctly heard Yvonne tell Mark 'I want you to kill him' when they were in bed together in one of the flashbacks. She sounded serious to me, and obviously to him as well!
Oh I think Yvonne wanted him killed and I think the fact that it was done exactly as she asked in bed- "I want you to smash his face in," indicates that Mark did it for her.
I haven't read the book which may have made it definite but I thought it was something said on the spur of the moment 'I would like you to kill him and smash his face in' because she felt so much anguish and hatred towards George at that time. From the televised drama I got the impression that perhaps Mark had Asperger's and took her to mean it literally whereas she just said it without truly meaning it - she just wanted the frighteners put on George to teach him a lesson and stop him stalking her.
Alima if you haven't seen Emily Watson before, try to find the film 'Oranges and Sunshine', a brilliant but heartrending portrayal of children shipped out to Australia:
Oranges and Sunshine tells the story of Margaret Humphreys (Emily Watson), a social worker from Nottingham, who uncovered one of the most significant social scandals of recent times; the mass deportation of children from the United Kingdom to Australia. Single-handedly and against overwhelming odds, Margaret reunited thousands of families and drew worldwide attention to an extraordinary miscarriage of justice.