I watched both parts on channel 4 a few days ago.
Interesting program and viewpoints overall, especially as I'm a young British Muslim myself, although certain parts didn't seem right to me but in general it was okay. It took in the most extreme viewpoints of both sides I feel, focusing on the vulnerable minds and confusion of what to believe is the right thing to do, using a death or hardship to drive the views into actions. I didn't like the ending much after all that and I wasn't expecting the whole video thing at the end either. Normally, I'm sceptical on these type of programs but this one touched on many of the views of what happens in reality.
Hope I haven't spoiled much of the second part for you but I guess you really know the storyline to it anyway - just from one point of view.