9cm!! That makes it even slightly bigger than mine...wow.
I have no information about overwintering marmoratus larvae and the size they can reach, but i definitely think this one has a chance of being paedomorphic. Keep us updated Ian. Wether it morphs or not it´s a very special and interesting individual.
btw...I can see a crest? i´m no expert at all, but if it was to become neotenic shouldn´t it loose the crest, as it is a juvenile characteristic?