Blown render? First off we need to know when your property was built at least to the nearest decade, vital if it's brick built. Then we can establish if it's a lime or cement rich render. If the majority of existing render is sound then we can either patch it or re-render over, if the majority of it is weak then it will all need to be broken off and then re-rendered.
Next you need to choose if you want coloured render or not. Surprisingly the two choices are very similar in price, traditional sand cement would be uncoloured and as a minimum left for a period of 1mm per day before painting which can lead to longer scaffold hire and future re-paints. Coloured scraped render (monocouche) is finished on the day and gives a remarkable finish and will never require paint. All my renders are manufactured, hold warranty and are machine applied giving us consistent mixes and speed. With all renders we install fibre mesh above/below stress points like windows to prevent future cracks appearing.