if you are asking this question i doubt you will do it in 2 hours. Removing the arm is undoing 5 bolts in total. 1 in each bush and two to the ball joint. Or you can drop the ball joint out of the hub. Then the ARB clamp bolt.
Once its off you need some sort of press to get the bushes out including some metal tubes to press the bushes with. Then you need to press in the new sleeves, tack weld them, put the bush in and bolt it all up loosely. Put the wheel on and lower the car onto some blocks so you can get under it. Let is settle for a while, then tighten the bush bolts with it in its ride height. Mind you just thinking about that in powerflex bushes the inner sleeve is free to rotate inside the bush so i guess actually you can just tighten it up before you put the wheels on. But i would let someone else confirm that.
If its your first time under the wheel arch of your Clio i doubt you will get it done in two hours. Its not difficult, but i have been going away at mine bit by bit over the last month but i am doing lots of little jobs while i have it on stands!