I did mine a couple weeks back, and it is a right ball ache
however the way I ended up doing it wasn't too bad with a bit of patience and time.
I used a set of large pliers like this....
I found them easier to use than mole grips. Then all I did was close them as much as possible and secure with a strong cable tie.
This brought the clamp closer to the subframe.
Then I used a small ish crow bar, or pry bar to push the clamp into position to line the holes up as much as I could then popped the bolt through enough to pull the crow bar away.
then I was able to put the nut on the back and tighten up.
It was very tight and like I said took a bit of time but I found it far easier tbh. Took me just over an hour to do the job.