Having no interest in removing my filters, I have just watched that video for the first time, and it looks a much better job than many of the strip-downs one finds on YouTube!
Am I right in thinking the latch for the 12-way connector is hidden at the far side from the camera? If so, this needs to be squeezed in at the cable entry end, and a built-in lever action opens the jaws at the lower end. The squeeze will need to be quite firm, but once released the connector should withdraw quite easily (although it is against the insertion force of 12 individual pins). As it appears to be proving difficult, I suggest using one hand to provide the squeeze on the latch, and the other to use a small flat-bladed screwdriver to get in under the flange at each end of the connector and ease the connector out that way.
My guess is that inexperienced technicians will underestimate the amount of squeeze required to release the latch. DO NOT pull on the wires!