I reparied the many cracks in my fronts with gell coat filler, you can get it in tubes, worked really well. Also put a bit of P40/fibreglass on the inside behind the worse damage.
Dremmelled the cracks out first, going right through the gell coat, filled & sanded.
Gellcoat filler sands really well, didn't need to use any futher fillers.
Scotchbrited the whole wing, used standard grey primer followed by a couple of rattle cans, looks great!