So the answer to the closed question"...are Euro emissions & fuel consumption more stringent than WLTP?', is?
There does not appear to be similar action with other Rest of World manufacturers, including a model they want to continue to sell in EU.
"...not place in unknowns that Audi have been unable to get their petrol engines through the new tests...". Was a firm belief. One may recall S4 production was interrupted early '18 due to test problems. To spend enormous Euros on a totally new diesel and timely, for cashflow, introduce it specifically throughout the "S" range, factoring in the time required to have all models in place to satisfy the fleet average rule, Audi must know what it has to do, and do it now. That is not rocket science, but plain commonsense. Again disclaimer - opinion only.