Is it possible to have a simple explanation for Simple Delivery from a seller's perspective? I did a test listing a few days ago having specified that I didn't want to use Evri as a carrier, and two options came up for delivery - Standard and Express. Is this Royal Mail Tracked 48 and 24, or a case of eBay overriding my choice and displaying Evri as Standard and Royal Mail as Express?

I was told last week in the chat that my choice of carrier would be overriden in "very specific situations". What exactly are all of these situations, seeing as Royal Mail appears to have more national coverage than Evri? It's only fair as sellers that we are told this.