I am trying to reproduce a boot spoiler from a hatchback car. The original is made from hard rubber - typical of the 80s I think. As its quite a complex Shape I was thinking of using the original as a plug mould and wrapping it in carbon? This would have the benefit of giving the original some rigidity as they tend to sag over time. 

Anyone got any advice? Ive trawled through the easycomposites menus but cant see anything that looks obviously like "resin" to seal rubber before using it as a plug mould?

Any advice appreciated!

Resin and rubber do not mix well, I reckon you will have difficulty bonding any sort of resin to rubber, firstly because of the chemical incompatibility and also because it is flexible. In your case I would use the rubber spoiler as a plug, pull a mould from it and then create a new spoiler entirely out of carbon fiber.