Have Royal Mail learnt nothing?
They should have got a respected US author to write the preliminary report and then got a German writer for the final report. The final report will show that the sub-postmasters were guilty as they had a clear documentation trail that they provided to the investigators.
When the preliminary writer questions the findings of the final report, Royal Mail mumble something about laws preventing the release of the preliminary report and wait for the whole thing to blow over. No one will remember this following the success of the Qatar World Cup....