Just posting a bit of an update really.
After playing around with it for a day, I've got my head around the shapes.
So anyone new to this puzzle, it's just like solving a 4x4 and is really easy once you understand (and remember) where the shape pieces go.
One tip is to solve the 4 fisher corners (4x4 centres) first and leave the top/bottom layers (white and yellow) last. Then you don't need any additional algorithms.
Also, what I've found is easier to do on the first layer, is to match/line up the 3 fisher centres (4x4 corners) and do the normal 4x4 algorithm to bring them from the top layer and down into position. (on the 4x4 beginners method, you position the first layer corners first, then the 2nd layers edges; I found it easier to position them at the same time).