Ok, I figured out (with a little help) the domino, or centre section of the cubic 3x3x4. When I got to the last 2 layers (top and bottom) I can't quite work it out.
I've solved everything except for 2 corners which are switched, and then something that looks like PLL parity on a 4x4, on the edges. If I hold Yellow top, Green Front, the 2 switched corners are up left front, and up right front. It's like a t-perm, but without the edges switched.
Then, the middle two pieces on right front, are switched with the middle two pieces in back right. They need a direct swap, like PLL parity on the right face.
Hope this has been clear, and thanks in advance.