Ummmmmmm don't you just love carriers.......

It is repairable and not hard,..even if the glass is cracked all the way through.

On the back feather out the crack with a wizzy then patch with resin and matt.
When that's cured you can attack the gel face, again feather it back with a wizzy then using pigmented gel with wax solution( top coat or flow coat) build up like using body filler.
Let this cure and sand it down using finer and finer wet n dry

The colour I used is super white pigment by west and senior, bout £6 for 500g from CFS.

I'm waiting to hear back from Emma on which carrier it was etc so will let you know.