With regard to the Mussels issue.
I think the beds in Conwy which cannot be fished form only part of the mussel beds available.
I say this because all the eateries in Conwy are serving Conwy Mussels (as opposed to Menai mussels).
Also, I was at Mermaid Seafoods in Builder St on Monday, and they had just taken delivery of an entire PALLET load of live Conwy mussels.
However, I agree about North Shore, they are certainly not to be eaten from there as they are not managed, monitored or tested to my knowledge.