The subject of “moves forward” is “union.” That agrees. The problem with that sentence is that the union moving forward doesn’t belong there and is awkwardly tacked on to the end of the atrocious syntax and indecipherable meaning of the passage “won the right to determine its own destiny to perfect.”
What I picked up was ‘the former colony’ after seeing Dinish D’Sousa’s 2016. Which seems to be a centerpiece of his ideological agenda as well as his Marxist ‘union’.