My issue is simply that we are lacking archaeological evidence for chariots in the area of south eastern England. That the Celts employed chariots is beyond dispute and their size and inherent production costs would restrict them only to the nobility as you say. Metal fittings (in particular the tyres) are substantial enough to allow archaeologists to conclude the presence of a chariot in a grave or context.

Simply put: Considering we do have archaeological evidence for chariot use elsewhere, is it not inaccurate depicting the Pritanoi using them when there is no archaeological evidence to support their use in that area?