13-03-2018 2:36 PM
Sellers can start an Unpaid Item case 2 complete days after end of auction. If they still don't pay close it after another 4 complete days to end transaction and get your selling fee back from ebay. So 6 days in all.
More details here:
http://pages.ebay.co.uk/help/sell/unpaid-items.html
Your method of postage is completely inadequate for the value of the item. If lost or damaged in the post you have to refund buyer, but will not get any compensation. You need Special delivery, but cannot ask the buyer for any more postage.