on your buyer requirements , you can block overseas bidders ..this will stop it  
  
No it wont. They will register with a UK address & then request the phone be sent to thier son/daughter in Nigeria. 
  
I sold a phone last week at the third time of trying. If the auction completes, email ebay with the details and tell them its a scam Ebay will refund your money & ban the user. Make sure you let Ebay know by email BEFORE you file a dispute because some of them will answer the dispute that they have paid/planning to pay & you dont get your listing fees back. 
  
This is happening too much on ebay, its happened the last 4/5 times ive sold phones on there