Standard sand and cement seems to have gone out of fashion over the years. The reason for this is not because it does not look good as a render but because when applied it does not tend to have a very long lifespan. Before you know it it will require maintenance and cracks will start appearing. Now there are many reasons as to why this happens, although the finish in sand and cement might look good it does not mean that it will last. The reason for this is because firstly if the applicator gets the mixture wrong then the render will most likely crack. Secondly the actual quality of the sand and cement when purchased from the builders merchants is not exactly great or at least not as good as it used to be. The sand is sold more or less with no preparation and it is still wet from the location it was sourced. Nowadays its all about selling in large amounts and it not about selling the right quality.
If you still want to apply a sand and cement render I would advice you to go for a ready mix render where you just add water to the mixture. The durability of this render is usually much better however it does cost a bit more then normal sand and cement. Also I would recommend fitting full reinforcement mesh on the rendered area as well as around the openings this will strengthen the render and enable it to resist cracking in the weak locations. A product that can be used is that from K Rend, the HP12 base coat can be used as a scratch coat as well to fix the beads and the mesh while the UF Base can be used as the finishing coat.
I hope this helps. I will write another post with more relevant information on this.
K Rend approved