Use leader/06 for 952y (item type)
Use PUBLISH_NO for 952h (Serial enumeration caption)
Remove a fixed FIXME
Move 300v to 300a
Handle multiple barcodes per item

As a beginning, different barcodes are trated as equals, and the first
on is put in 952$p, and if there are any more they are put in 952$z.
Might have to refine this later on!
Stick a notify-send at the end of the script