ALL the convictions should be overturned now. It's appalling so few have been so far.
Agreed. Including the appeals that the Court of Appeal has rejected. Given the level of wrongdoing in Post Office that has been exposed by the inquiry, every single conviction should be overturned. Yes, that may mean a few people who were genuinely guilty have their convictions quashed, but that would be a vast improvement on the current situation.
Surely any log of entries/changes which doesn't make a record of who made the changes isn't worthy of the name log? ie essentially worthless - essentially not a log?
In theory it did. It showed which terminal was the source of the entries. The fact Fujitsu engineers didn't follow the correct process when making modifications to branch accounts undermined it.
I don't understand why there wasn't some sort of report facility in the program, so that the postmasters could see what entries and figures the program was using to calculate any "shortfall"?
Post Office didn't think that such a facility would be of any use. The subpostmaster in his or her branch simply didn't have the information needed to see where any alleged shortfall came from, nor did they have any mechanism for challenging it. For a long time, Post Office insisted that Horizon had a "dispute" button that a subpostmaster should press if they didn't agree with Horizon's figures. They were eventually forced to admit that there was no such button, nor had there ever been one.
If a bank sees a shortfall in a branch, it has to cover the shortfall itself (unless, of course, it can prove theft). It is therefore incentivised to ensure that its systems are error repellent (i.e. they make it hard for users to make mistakes) and to investigate shortfalls properly. Post Office had no such incentive because they could simply push any shortfall onto the subpostmaster.