Sorry, I should have been more clear in my language regarding the driver update. In our testing of the HD 4600 (another Haswell series GPU) we have found that we can walk up and down through the driver versions with older versions crashing (specifically 10.18.10.3496 is known to fail) and newer versions working (though I forget where the exact fail / pass threshold falls within the version numbers in our testing).
So my surprise was just that updating the graphics drivers did not get a version that is new enough to fix the problem and was not a comment on that particular driver version.
One complication in all of this is that Dean is running Windows 8 as opposed to 8.1 which may limit the maximum driver version he’s able to get from Intel or Lenovo. However, the Intel driver downloads page indicates that he should be able to get something newer. For instance, I see 15.36.23.4251 as being available for Windows 8 (32 and 64 bit).