Not only did I look at your photos multiple times, as a suspension and alignment specialist I've replaced a lot of these rear shock absorbers over the years. Some took me almost three hours to do a pair of them, and they always involved muttering under my breath that an engineer could design something so miserable to work on. To add to the misery, the top nuts usually are rusty, so wrenches won't grab well. My best approach was to grab the top nut with a Vise-Grip pliers, then grab the steel cover and turn it with my hands. In the '80s and '90s they didn't even have the thin nuts on top of the covers.
Some of these shock absorbers had soft plastic covers. On those you can cut the covers off, then grab the shafts with another Vise-Grip pliers after grinding some flats on them.
I have never had one of these where I was able to unscrew the top nut, as you are hoping to do. At one shop I worked at, we weren't allowed to have a torch because we were attached to a shopping mall. Most of my success came with using a cutoff tool with a 3" metal-cutting wheel to cut through the shaft just below the upper mounting plate. Later, when working at a very nice dealership, the torch made quick work of the upper nuts, as long as there wasn't the typical leaking gas tank.
By the way, those upper nuts started life as 15 mm nuts. If you're trying to get a 14 mm on there, the nuts are already rusted away and the threaded shaft is going to be the same. You're never going to get those nuts unscrewed, so you can resign yourself to looking for a different way.
Sunday, September 6th, 2015 AT 7:34 PM