My CV boot on my Vrs with only 13000 miles on clock has just split and covered the O/S/F of my car with black grease, the boot was split along the leading edge, I always thought they were made of rubber but the OEM one was a hard plastic which has me thinking that was probably the reason it split in the first place, any thoughts please.

Cv boots and the like are made up of predominantly neoprene. This is impervious to oil, and grease and resistant to high temps. Rubber as you probably know is not and would be damaged if that was used. Neoprene has rubber type properties similar to natural rubber and synthetic rubber but is totally unaffected by the oil and grease it holds in and is much more temperature resistant, so is used for just about everything requiring flexible properties in motor vehicles including seals, hoses, cv joint boots etc. If yours has split it had a weakness most likely from new or it's been damaged by road debris which happens quite a lot. That's why at service each cv joint is checked for wear and damage. Sometimes a cv joint may be damaged and not noticed, if major work on the car is undertaken. Has yours had any work done recently that required drive shaft removal?