Complex sentence: While disappointed with the initial results in the 1983 local elections, Koritzinsky was pleased with the overall outcome of both the Socialist Left Party and the Labour Party, but was worried of the increased interests right-wing parties, especially the Progress Party.
Split into simpler sentences: While disappointed with the initial results in the 1983 local elections, he was pleased with the overall outcome of both the Socialist Left Party and the Labour Party. However, he was worried about the increased interest in right-wing parties, especially the Progress Party.