Backlight working but no picture, after a screen replacement

Having recently replaced the touchscreen on my Surface Pro 2, and initially getting nothing on-screen, despite numerous force reboot, I managed to get it hooked up to an external monitor in order to diagnose. The first to note at this point is that the backlight and digitizer are both working.

As far as the device is concerned, it doesn't think there is a problem with the screen - it detects it in Displays, adjusting the brightness results in changes in backlight brightness. Disabling and re-enabling the screen in Device Manager doesn't have any effect, other than to turn the backlight off and on again. Also running the Surface Diagnostic Toolkit doesn't reveal any underlying problems that weren't already apparent.

So this leaves the replacement panel itself, the ribbon connecters and the sureness of the installation. All the ribbon cables look undamaged and the connections have been reseated several times to ensure that they are good, however before I embark on what I know will be a lengthy exchange process, I want to make sure that I can only be a fault in the new screen.

Have I missed anything? Is there anything else I can check?