Mould making mistake ?

I have recently took the plunge into making a carbon fiber part for a GT style wheel plate that i use to my hobby that is Simracing. The part was skinned with Carbon vinyl and i wanted to make the part as part of a educational project since taking a plastic makers education here in scandinavia.

The part that i will be making a a mould from is a one piece of acrylic that has been painted black.

All the sharp edges has been sanded down so that laying the carbon mats in the mould wouldn't be a problem.

I have followed all the procedures explained the here:http://www.easycomposites.co.uk/Downloads/TDS/EC-TDS-Epoxy-Mould-Making-Kit-Instructions.pdf

using both the wax release agent and the PVA to ensure that the mould would easily detach itself from the part.

but my real problem is that now that the mould has fully cured i doesn't seams that it is separable.

I have used plasticine to close all the holes in the part.

-I have ensured that there is no mechanical lock at all visible side by means of working the part with a dremel tool just to be certain.

Stil the part won't come off!

I don't know it if i used too much putty in the making; i could had used 1/3 less putty material and at some parts the putty is more than 2 cm thick.

So I Would be more than glad to hear from all of you what mistakes I have done and what course I should have done instead.

Last i would like to hear if it's still possible to take the part out without damaging both the part and the mould or if it is a total redo Whistling

thank you for you time

Santana