Can someone please grade this for me?

It's an A levels Law activity from my textbook. But of course I can't grade my own work.

Questions:
In 1952, police officers discovered Derek Bentley and Christopher Craig attempting to burgle a factory. Bentley was aged 19 and suffered from mild learning difficulties. He did not have a gun and quickly gave himself up to the police. Craig did have a gun and he fired it, killing one of the policemen. Before the shooting, a police officer shouted to Craig to hand over the gun and Bentley shouted 'Let him have it, Chris'. The prosecution case relied on Bentley's shouted words. The prosecution alleged that they amounted to an incitement, or encouragement, to Craig to shoot the officer. The defence argured that Bentley meant 'hand over the gun' and he was trying to satisfy the police orders. Bentley was convicted of the murder of the policeman, despite neither possessing, nor firing, a gun. He was sentenced to death. Craig was, at 16 years of age, too young to be executed and served ten years in prison. Bentley was one of the last men in Britain to be executed. His conviction was eventually quashed in 1998, after years of campaigning by his family.

1. Was it just that Bentley should be found guilty of murder and executed? Justify your views
2. Explain the meaning of the phrase 'quashing a conviction'.
3. Who makes a decision to quash a conviction?
4. do you think that justice was eventually achieved by the quashing of the conviction?

My answers:
1. No, because he has learning difficulties and gave himself up to the police quickly, that would likely mean that what he meant by ‘Let him have it’ is ‘hand over the gun’ because he didn’t want to cause too much trouble. Also, he didn’t even shoot the policemen. If what he meant by ‘Let him have it’ is ‘Go on, shoot the police officer’, he didn’t shoot the gun. Craig, who had the gun, made the decision to fire the gun himself. And finally, they didn’t burgle the factory, they attempted to burgle the factory, which means that they didn’t succeed in burgling the factory. I do agree with Craig’s sentence of 10 years in prison, but being executed for not murdering the policemen is too much.
2. To say officially that an earlier decision is no longer put to use.
3. The Court of Appeal
4. Yes and no. Justice for Bentley, no, because he was already executed, and that still brings pain to his family, I’m sure. But, justice is achieved for everyone else after the quashing, who would have been executed if it wasn’t for the quashing of the conviction.

Please grade it in percentage, and grade the grammar and punctuations as well. And if it's not too much hassle, what would you put as the answer. Thankyou