I found it a pain to cut in-situ, but your eyes are probably better than mine. I decided to remove the wishbone for the other side. As said, be careful not to cut into the wishbone.
Having replaced bushes on other cars, I'd need a bloody good reason to even consider trying it with the wishbone on the car! All the descriptions of how it's done reinforces that opinion. After all, it's only two more bolts, and it means you can evaluate the rear bush and the balljoint. As for doing it with the car on the ground, you must all be mad!
Don't knock it 'til you've tried it. Or seen it. Its easy. 
Poly wishbone bushes on mine. Plus the anti-rollbar ones(I wouldn't bother with them again). Replaced the rear bushes and balljoints while I was at it. There is no way I'd do any of this with the wishbone on the car.
Each to their own. But obviously I was referring to the process of fitting poly with the wishbones on the car. You can't really knock it, until you've tried it. It really is very doable. A one or two spanner job, in Haynes parlance. Especially for someone as handy with spanners such as yourself.
Also, obviously, if the rearward vertical bush is buggered its a bit pointless. May as well remove the wb's.
Don't want to be picky on a very helpful video, but to save some possible unnecessary agro...
Turks video mentions undoing the rearward bush bolt, there is no need to undo that rearward bolt.