The face dimensions of a concrete block in the UK is supposed to be 44cm wide x 21.5 cm tall, giving an area of 0.0946 sq. M.
Total wall surface is 22.08 sq. M.
So, the number of blocks needed will be (22.08 / 0.0946) = 233.4 blocks. So you should order about 240 pieces, or more if they are hard to get. Don't forget to order reinforcing bars as this is a rather thin wall (10 cm). In fact, I would suggest incorporating a buttress every so often to make it more rigid and also to look better. For that you will need a lot more blocks.
Good luck.
Total wall surface is 22.08 sq. M.
So, the number of blocks needed will be (22.08 / 0.0946) = 233.4 blocks. So you should order about 240 pieces, or more if they are hard to get. Don't forget to order reinforcing bars as this is a rather thin wall (10 cm). In fact, I would suggest incorporating a buttress every so often to make it more rigid and also to look better. For that you will need a lot more blocks.
Good luck.