I just bought the bushes from a local motor factors as they do the same job! Handy enough to fit and the easiest way is to drop the whole lower control arm out and have it flat on the ground so that it can be simply knocked out with a brass drift so not to damage it. The bushes are tapered and need to be knocked out away from the car and in towards the car. There are videos on youtube to show how this is done. They can also be pressed in and out but requires the LCA to be completely detached from the car!
All of the above parts are not necessary but if you already have them it will make things a bit easier.
These bushes normally knock in and out quite easily using a brass drift and try to hit the bush evenly at both sides of the circumfrence if that makes sense. Also it is very important to remember that when knocking them out hit the bush towards the outside of the LCA and when knocking them, towards the inside of the LCA as they are tapered. Measure the distance that they are pressed into the LCA before removing and also the rotation of the shaft through the middle
If none of the bolts are ceased it will prob take a few hours. But if it is a uk car then it is likely that some of the bolts in the rear control arms may be ceased to the bushes so try them 1st and see if they loosen ok. If you are unsure of what you are doing I would recommend just leaving it into a local garage