Complex sentence: Bill and Imelda Roche AO established Nutrimetics International (Australia) Pty Limited in 1968 and 23 years later, in 1991, acquired the worldwide interests of Nutrimetics International.
Split into simpler sentences: Bill and Imelda Roche AO are Australian business persons who established Nutrimetics International (Australia) Pty Limited in 1968. In 1991, they acquired the worldwide interests of Nutrimetics International.