1. installed the WDS role on WIN2012R2 in standalone mode,
2. installed Win7Pro on a reference machine (I have tried both a VM on an esx host and a physical box)
3. added a boot image from the install media used above (sources\boot.wim)
4. In the case of the physical machine, added the NIC drivers to the boot image created above
5. Created a capture image from this boot image as per https://technet.microsoft.com/en-us/library/jj648426.aspx#BKMK_CreateCustomInstall
6. ran sysprep.exe /oobe /generalize on the reference machine created in 2 above
7. Booted reference machine from NIC, choose the capture image and am presented with the attached screenshot, I have tried this multiple times using a VM & physical reference machine and using different install media, I must be doing something wrong at the capture image creation stage but Im sure Im following the documentation.