Rendering acts like a raincoat to the exposed blocks and what is crucial to understand for any exterior surface, but especially the highly porous breeze blocks, is that moisture is not allowed to absorb into the substrate, which will cause damage not only to the paint work but to the material itself.
the more they are exposed to elements the more they will degrade overtime.
i would highly recommend you speak to a qualified and knowledgeable builder about reapplying render to the property sooner than later after old removal to minimise property damage and further protect your house.