Thank you Daisy, for bringing this case to our attention. I have been reading all the newspaper reports from when Mark was arrested and convicted, as well as the posts on the forum. I had not previously heard of this case.
Mark had a motive to kill his father, but that does not mean he did. There does not appear to be much evidence that he did, apart from the fact that he had a strange relationship with Samuel, and he had access to the property.
I am surprised that the prosecution was unable to make a more precise estimate of when Samuel was killed (have heard this kind of thing before!). The neighbours sound weird too: in the newspaper reports, they appear to be very concerned about Samuel's whereabouts, and suspicious of Mark, and at the same time, there are all these quotes about how difficult he was, how they didn't get on with him, and how badly he treated his son.
It is not clear whom Samuel knew, and what "enemies" he had. A number of people could have had a motive to murder him. It appears that , at the trial, Samuel's lifestyle, and the people he knew, was not gone into very thoroughly.
This case has sparked my interest, and I look forward to learning more.