Are the certificates of Dualsun panels issued by an accredited certification body?

Yes, The IEC 61215 and IEC 61730 certifications of Dualsun FLASH panels have been issued by the TÜV SÜD laboratory, itself ISO/IEC 17065 certified by DAkks, the German equivalent of Cofrac.

The IEC 61215, IEC 61730 and ISO 9806 certifications of Dualsun SPRING panels have been issued by the European KIWA laboratory, itself  ISO/IEC 17065 certified by ACCREDIA, the italian equivalent of Cofrac (FR)

Accreditation from Cofrac, or another European equivalent abroad like DAkks in Germany or ACCREDIA in Italia, recognizes and certifies the skills and impartiality of certification bodies at national and even international level.

 You can find all certifications here.