Thanks for your helpful reply.

I had no active or draft listings when SD was brought in, so at least I didn't have the headache of eBay changing the postage. What a nightmare!

Yes, there seems to be a difference between taking the package to the PO with the label already attached and getting the code scanned at the counter.

I'm very curious about the idea of taking the package to the delivery office instead - can they print the label from your QR code? I don't have a printer. And I assume from your post that they don't measure and weigh the package - is that correct? Or is it simply that RM are more au fait with SD than some POs, and know that they can accept an item with underpaid postage if it has a 'Marketplace seller' label? Sorry for all the questions, but I'm very interested as this might be another option, even though my PO appears to be more or less up to speed.

I posted elsewhere today about a conversation I had earlier with my PO manager, so won't repeat it all here, but basically she said that they were aware that they should accept a package with an underpaid label provided it didn't exceed the maximum size and weight limits for RM (Medium parcel not exceeding 61 cm x 46 cm x 46cm, weight 20kg or less). So it looks like I'd be okay in that respect now that they're getting used to what is, to them, a big deviation from their normal (non-SD) way of doing things.

I owe thanks to SD for a couple of things.

Since the start of the rollout and the many discussions about SD, I'm sure that my brain capacity has increased! I'm having to absorb and remember lots of facts and changes, as well as having to apply logic and reason - I'm certainly being kept on my toes! I'd much rather be directing that mental energy elsewhere, though.

And, secondly, it's made me come out of my shell and post here more often, even if the TL;DR contingent don't see that in the same positive light that I do! It's been enlightening and enjoyable having the odd discussion with other members.