After less than 2 months of investigation (if you exclude time between the correspondences) the ASX found irregularities and a series of issues associated with ISX's revenue for the relevant period. The ASX also found that ISX had breached multiple listing rules.
Every investigation invariably starts off with a suspicion raised by a source. It doesn't matter what the actual source is as long as the suspicion is strong enough to warrant an investigation. A suspicion does not necessarily have to be substantiated, which is why it is called a suspicion. In general, a lot of cases of fraud had been uncovered as a result of media coverage and third party analysis or reports. Some examples include wirecard and more recently Nikola.
Satisfactory according to who? The independent reviewer have stated that they have based parts of their report on assumptions. The report also did not cover any of the four contracts. The only thing that you can learn from the report is the fact that ISX has not signed any material contracts after the four key contracts, which should ring some alarm bells.
No, because it contains blatantly erroneous and misleading information, for example the one pertaining to 15 percent revenue representation to analysts.
Why should anyone? Grant Thornton relied on certificates of completion that the ASX found to be riddled with glaring issues.
An auditor could only work in good faith with what is given to them.
