Simple Delivery has been enforced because it is another way for eBay to make a profit - eBay have a contract that makes them money with every EVRI usage. Not sure about Royal Mail!  I agree, it is rubbish & like many others, I've taken all my listings off.   

eBay, without any advice to me, added a Simple Delivery charge to all my carriage inclusive items & that did not show up in my eBay Seller Summary, so I had no way to know why sales had suddenly dropped.  This eBay scheme is nothing more than a scam.  It is impossible to offer inclusive carriage, it is impossible to add carrier insurance.   It is, I assume, designed to force private sellers to become business sellers, who do not face these limitations.