Unresponsive to touch - 5cm of screen after digitizer replacement

I have just replaced a cracked screen on my iPad 3 for the third time. First two replacements were fully functional, just not glued effectively, hence number of replacements!

This time around however, I appear to have done something to compromise the left side of the iPad - if you hold it portrait with the home button at the bottom, the first column of icons is completely unresponsive to touch, while the other three columns continue to respond.

Both the touchscreen and the display module appear to be reconnected well, though I have rather carelessly clipped off a small piece of covering off one of the two touchscreen PCB ports.

I have a picture of that if it might help anyone suggest what I am doing/have done wrong! Any help greatly appreciated, I have looked for an answer to this and not really found anything, regards, Allan