Hi CloverQ I appreciate your response, but there isn't much help to be had in what you have said.
We are working on the Desktop (not Cloud) version of the product, as the online version doesn't support multi-currency and does not even seem to have the concept of an Order, so add-ons are not of much use.
The report you mentioned only exports a single summary line per order, whereas the Export Item Sales exports all line items of the order, which is the data we need. Other reports that do export line item data for orders don't do it in a consistent single record format, so again of no use.
It is simply not acceptable that basic and documented functionality of the product can have known bugs in it for a period of 2 years, and simply be ignored and remain unfixed.
This bug will eventually swamp our downstream software with extraneous data, and if we cannot resolve the issue we will have no choice but to seek an alternative solution for our accounting needs.