To continue this saga..... I've got my order ready to post to the customer - on Sunday the 24th August, and that's well before the 29th when eBay say I must dispatch by. So I clicked to get the pre-paid label, and was astonished to see the message that I must post the item by the 23rd! The day before! Now, I can't post on Sunday - nor Monday, which is a bank holiday - so I'm going to post on Tuesday the 25th, still in time to meet the original deadline.

I'm totally fed up with all this fuss. 

I'm going to try one last time, creating a listing with free delivery, and see if I can bypass the simple delivery option that way, and if it works, I'll just have to add the p&p price to my item prices, but honestly, if it doesn't then I'm finished with eBay.