original: Though not popular, herring roe is sold within many British supermarkets.
simplifications: Herring eggs are not so popular, but are still sold in many British supermarkets. Though unpopular, herring roe is sold in British supermarkets. The unpopular herring roe can be found in many British grocery stores. Herring eggs are sold in many British supermarkets. However, they are not popular. Herring roe is sold in many British supermarkets. It is not popular. Herring eggs are sold in many British supermarkets. Herring roe is sold at some British supermarkets. It is not very popular though. Herring roe is sold within many British supermarkets though it is not popular. Herring roe is not very popular. Even then herring roe is sold in many British supermarket. Although not popular, the herring roe is sold in many British supermarkets.