By Carolyn Cohn LONDON (Reuters) -Chemical groups BASF and Solvay are among 12 European companies to join cyber mutual insurer Miris, which on Wednesday said it had received an operating licence from Belgian regulators and would start offering insurance from Jan. 1. The mutual insurer, a structure in which the company is owned by its customer members, is looking to meet increasing demand for cyber cover due to rising attacks, Chief Operating Officer Mark Pollard said by phone. The new insurer is also talking to some 40 others about joining, he added. Germany’s BASF is a member of Miris, a spok…