Always call BT 188 188 and check to see if the buyer's name is registered at the address given by asking for the phone number of the person at the address given. Check that the address and post code is valid with royal mail and research the origin of any name given. If any of the details to not correct inform eBay immediately you may find.
Always allow cheque or Credit Card payment to clear and only dispatch after the clearance process has completed. On high cost items with foreign customers you may wish to use a suspense bank account, that has limited facility for withdrawal and perhaps not internet facilities. Please note that not every country in the world has the same banking and cheque cancellation periods. Check with your bank that the cheque or payment has cleared and the cannot be cancelled or withdrawn before dispatch.