Hi,
Regarding warehouse bay locations: For every PDF invoice generated, we need each product listed on the invoice to show where the product is located in our client's warehouse (i.e. each product is in a storage rack within the warehouse known as a "bay").
So the main question isn't whether we can customise the invoices (we know that's possible), but whether your software allows each product to have its "warehouse bay" location set somewhere, so that we can use custom code to display it on the invoice.