Well...this is what I was after. I don't know the size of this, but it's the perfect shape and design. Only problem is that I need 6 of them and after much hunting it appears these are not available as spares. You only get them if you buy the whole kit, really don't want the whole kit, especially not 6 of them for a one off - nor if they do not fit the cars (below)
http://www.tamiya.com/english/produc...za07/index.htm
If anyone has any ideas, whether another manufacturer does these shells please let me know. (For shell sizes they need to fit cars like - Serpent S400, Schumacher Mi3, Hot Bodies Cyclone etc)
Many thanks
Ben