Showing and hiding rows and columns in a Pages table

I created a Pages document a while back that has several rows and columns hidden. I need to duplicate that table but make some changes to the original and the duplicate. For the life of me I can't get the rows or columns to "unhide"!

I've selected the columns on either side of the hidden ones and tried to change the width but nothing happens. Same with selecting the row above and below and changing the height. Nothing!

It would be great if I could expand the table out in Numbers. Work with it there then import it back.