I know that David Walsh is a serious journalist but unfortunately the Sunday Times is behind a paywall and I prefer not to add to Rupert Murdoch's billions, so I haven't read the article you mention.
As for Irish racing being in chaos, I'm not sure if that is the right word at a time when on the surface things are on the up. I don't remember a time when there has been so many good horses in the country, both flat and jumps, attendances have started growing again and finances will improve next year.
By the time the Fenton case finally came to court the affair was already jaded news, but as a result of it we have moved from believing there was no serious drug problem in Irish racing to one where we know a crooked vet imported enough steroids for 62,000 doses and had the names of 12 trainers on a contact list, including Pat Hughes and Philip Fenton.
We also know that the main drug concerned, nitrotain, leaves the system within days and cannot be detected by standard race day tests. Because of this the Turf Club has had to introduce a programme of testing at trainers' premises but it is probably not enough. First, the number of tests being performed is minor enough. Second, the tests are only carried out on horses registered as being in training, which is a big loophole.
Current practice allows a horse to be out of training until days before it runs in a race, so injured horses, horses on a break and horses which have not yet run might all be under preparation for a race but are not subject to testing.
These are issues for all racing countries, but as a big exporter of horses Ireland needs to deal with them more than most. I don't know if the authorities have yet made the cultural shift needed.