It doesn't take that long to pull the heatshields out, then the job isn't that bad. Other than that I have just stuck a wrench through from the top and used wood to hold it then go underneath and loosen the bolt. You have to stop before spinning it all the way off though, you go up top again for that so you don't lose everything.
On thinking about it, you should be able to hold the front wrench somehow along the crossmember and loosen from the top,
Sheldon