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no 'duty of care' on the manufacturer. they may have a product liability if the product was not in line with advertised specs.
A much more likely question is whether the parties that specified and approved the cladding were negligent in performing their contractual duties when making the recommendation to use that particular specification of cladding.
The only people that might have a duty of care is the building's managing agent, but that is beyond my knowledge
Guardian confirms they used the cheaper cladding
https://www.theguardian.com/uk-news/2017/jun/16/manufacturer-of-cladding-on-grenfell-tower-identified-as-omnis-exteriors