Thanks for another very helpful reply!

I assume where you typed "the QR itself doesn't say anything about email or simple delivery" this was an autocorrection of "eBay". 

I'd need the label already if taking to the delivery office - noted.

Thankfully, my main PO seems to be on board with SD for the most part. It's a bus ride into town for me. I do have a PO inside a Spar just a few minutes' walk away, but I'm not so confident that they'll know the score.

Yes, this does seem to be the reason some POs are still struggling to get their heads around it all. And the discrepancy between the appearance of self-printed labels and labels printed at the PO counter from the QR code is confusing us sellers.

With my currently-listed item, it's a moot point now, as I've erred on the side of caution, ignoring eBay's recommendation and selecting a size and weight band that my item is completely within. So, in theory, I should be okay now even if I took it to the Spar PO.

This is quite a learning curve!