BangOr - I don't see why it couldn't be replaced from the back side. Are you sure you want the same valve? Seems like a lot of trouble.
I too, have the 34-436 and it's leaking. I replaced the stops 10 or so years ago and the thermostatic valve is tempormental. It's damage my ceiling below two times, I would not buy the same valve.
In an earlier post, you mentioned having trouble getting the thermostic valve out of the body and then you posted you got it out. How did you get it out? I can't get mine to jar loose either. Grohe suggested spraying vinegar and water solution inside the body. How did you do it?