Reports on these nucs from Park beekeeping might be enlightening with regards 'chewing' by bees. I have some e-mails which were decidedly off-putting for me. The density of the polystyrene in their product is likely still exceeded, by some suppliers, by more than 25% (unless they have increased it further, since I was in contact with them). I declined their offering, although the product seemed to fit my other criteria, and am eagerly awaiting news from Rooftops (Modern Beekeeping), here on the forum, regarding what I believe to be a much superior material. Not tried a polyhive yet but I can say one of the local BKAs purchased a pallet of polyhives from Modern bekeeping and have been pleased with the product.
Regards, RAB