Nevermind my last post! I think I figured it out! Had to dig back to the 8th page of this thread.

Just to make sure I haven't in some way made something worse, I just want to make sure I have, now, correctly followed Step #2 of the installation readme for RPM.

From the reward points diagnostic module I know that my custom folders are named "classic", so where ever I have found a folder actually named "custom" I have copied its contents into the folder named "classic" which exists at the same level in the tree.

Is that the correct method? I have only had to do this in 3 places, I am running a fresh Zen Cart install, with RPM being the only mod. After doing this, the sideboxes appeared in layout control as expected.

Dennis