Only post to the address which is shown on the order details.
Do not send to an address which is different and particularly if the buyer requests this.
If it is eBay saying not recognising the address by adding a different postcode or road... message your buyer and ask them to confirm the address in full and only post to that address. as long as it matches the sales order address. I have had this issue before whereby ebay " auto" doesn't recognise but it is the correct address and confirmed it with the buyer.
Hope this helps.
