So what the above suggests is that to accommodate the new VAT rules we cannot simply change Zen Cart to automatically generate emails to Customers, that attaches digital content.

What we would need to do, is add options to Zen Cart to disable the automatic download of digital goods.
The order system in admin would need to have filters added to easily identify Digital Sales.
Shop owners would then need to manually send emails to customers providing links to downloadable content.

Note here, my reading is that those links could still be to the Customer Account area, which is where previously customers would have downloaded stuff.
It's the actual manual part of sending the email that is important.

Ian