So, I have a large split mould that I'm bringing together to finally infuse. I've ran a bead of silicone between the mating flanges to help defend against air ingress. A tiny bit of silicone squeezed out onto the mould surface. 

Normally silicone is selfreleasing to most materials and epoxy is normally one of them... 

I am planning a split mould too, and was thinking I will go one of two ways. Either envelope bag the whole thing like matthieu said, probably easiest and will result in least headaches....