After getting nowhere with Applecare I decided to email Tim Cook. A couple of days later a lady contacted me who works for the Executive team and is based in Ireland. I explained my problem to her and she told me the following: Apple are well aware of the problem and it is making its way through the various engineering departments. The fix being worked on is a software fix. There is no date for launch but she believed it should be fairly soon. After discussing things with her I have decided to keep my first machine and return the second. If the software fix does not fix my machine she will replace it for me. So, fingers crossed guys!