I fail to see what you are getting at Justice K, He was charged with JE and found guilty as charged.
JE is laid when those involved jointly embark on a crime, in this case they clearly did. After conviction Fuller seemed to accept his guilt and passed through the system as such, on the other hand Craigie maintained innocence which must have hindered his progress through the system.
Although Fuller in a statement to his Probation Officer took responsibility for the Murder, they were both still jointly involved in the Joint Enterprise, and in English Law it is irrelevant who struck the deadly blow, they were both involved and as such both were guilty of the index offence of Murder.
Having read his Police Statement made at the time he clearly admits being there. He made no attempt to save the Mans life, He did not contact the Police, or even dial 999. He left him to die. So therefore he must be guilty as charged.