@Tom-Elliott It appears that the OP is using the 1.2.0 stable image on pretty new hardware (2014). It was my understanding that 1.2.0 stable had issues with uefi image deployment. It would capture the image no problem but it would not lay it down correctly on the disk. It was my understanding that it was fixed in the mid 4000 range of the Git trunk. Is that accurate? For me I would recommend the OP upgrade to the latest SVN trunk, with the understanding it is still beta and pre 1.3.0 release (i.e. there may be a few bugs in the system, but they will get stamped out pretty quick).
 corrected a grammar error in my post [/edit]