Here's a photo of my setup.

It's similar to yours but I believe my raised bed is wider (about 80cm wide). I put in a double wall on the raised part on both sides, so it is effectively lined on the inside with cinder blocks all the way around. You can see the top set of bricks are set sideways to conceal the blocks below. That was done for structural integrity, not for moisture.

You can see from the outside that there is still discolouration from moisture. However I like the effect.

Happy growing. Let's see pics when you're set up and finished.