WOW! Sharp eyes Tench.
I have just looked at the original photo and there are two V shaped splits in two pellets.
Right, I'm off to sort through my pellets before tomorrows competition.
EDIT: 2 x dented and 17 x split skirts, mostly a tiny little vertical split about 1mm wide and 2 mm deep, through to one with quite a noticeable V in the skirt.