Garden wall - Which block/alternative

[Phoenix830]

Hello

I have a "garden wall" that had been made out of metal bound wood. This has become unstable and any pressure on it causes it to break. I am going to be building a new wall and while looking for breeze blocks came across Dense Blocks. At Wickes there are two types; Dense and Medium Density both at 7.3 N.

Could someone please advise me on the difference and or an alternative.

If dimensions help the width of the garden is 8.4M and about 2M high. It will be holding back soil with block paving or slabs on. When building the wall I will be removing some soil and adding sand weed control fabric.

Thank you for any help you can offer

 

[Phoenix830]

The Height is more likely to be 1M to 1.5M