As above.

One other thing to note is the change of colour in the dust (white to gray) if you hit the cloth.  If you get this STOP sanding!

What he said!

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Theres a very significant change on the surface when you hit the carbon. It's like the light hits the carbon strands differently, You will know when youve sanded enough. It doesnt matter if you sand into it, but you can sand through it if you just plow through it. The surface layer is at least .25mm thick, if you sand through it, youll see the weave from the layer below it and it will look naff. Use 300-400 grit to get most of the lacquer off, then move onto 600-800 to get the last bits.

I'm a bit worried about sanding too far because I haven't done any carbon work before. I'm not sure how far down the de-lamination has occurred, in one spot it almost looks like its between the weave. 

Do it yourself, sand it back to carbon then re-clear it and polish it.
Or get someone to clear it for you, but definitely sand it and polish it yourself, that's where most of that £150 is. Body shop should be able to clear it for £20 if they can fit it in their batch.

Hi all,