hi Andrew,
I believe to see that you have two times 6 connections wired. The display needs exactly this twelve connections. Your picture shows, as I believe to see that you have on the display only 3 pins left in the middle. There should be 4 pins spare. Same thing at the controller- board, It seems to be no spare pin in between the ribbon cables. You must connect pins 1 to 6 and 11 to 16 with the display.
verify this!
73, Immo, DL5KB