the UK government has issued guidance on the new 10p carrier bag charges. and while the guidance states that;
‘ You’re not required to charge for plastic bags that are solely used for uncooked fish and fish products’
There are other factors that might influence whether you have to charge for bags – if you have multiple different products in the same bag, read more of the guidance at:
https://www.gov.uk/guidance/carrier-bag-charges-retailers-responsibilities