I was able to attend a Q and A with Peter Dinklage a few days ago. Didn't reveal anything except he starts back this week, but also because he mentioned he hasn't read the books either apart from the first one so he only knows what's going to happen from the scripts.
He also mentioned that the film out of sequence for the whole season so he could be doing something from Episode 6 before going back to something from 1, 2 or 3. Makes sense though I assumed before they filmed each episode before moving on to the next.
Regards Tyrion as the best role he has ever had. Lena Headey and Jason Momoa were also there but I missed their presentation.