Marshalls croft stone walling height

[jimsalabim]

First post here. Sorry if this has been discussed before.

I'm planning to build a 1000mm~ heigh retaining wall in our garden to replace rotten round posts.

When shopping around the best option seems to be the Marshalls Croft Stone Walling. I like the idea of the interlocking lip on the back of the stone since our garden is sloping towards the wall.

Have anyone worked with these stones before? Marshalls state the max allowed height is 600mm. Why is that? Can I strengthen the base to allow more weight?

Attaching a rough render of what I'm trying to achieve.

 

[Mr Chibs]

I've used these before, about 5 courses tall, you can make curved walls as your mock-up (not quite as tight though).

I wasn't aware of the limitation of 600mm, but don't really think it would be problem making it taller.
Each course of bricks sits back 25mm or so from the course underneath, they are hooked onto the course below with a lip on each block.
I would backfill & tamp (block of wood) with soil as you work up the courses.

You may need to sit it on a footing, mine was on compacted hardcore and has been fine so far.