I want to try resin infusion on this.

I think what im trying to say is because i dont have a mould with an area around the mould to fix the bagging stack to, will the resin flow ok through the material. ? 

not heard of anyone trying it that way.  Youd realistically need a flat surface to stabilise the bagging stack, eg if its flatish part you could lay it on some polyprolene sheet. Youd have to lightly glue it down, and seal the holes and edges with wax, but it should give you a solid enough surface to do a one off part without making a full mould. If theres a big curve, the air under the part could be an issue as the wax in one place will pull out as the vacuum draws to draw air out under the part.

You could of course make temporary flanges on the part and envelope bag the whole thing to give you the rigidish edges you want to give a clean edge line.

Went back to drawing board and came up with some extra flanges.