I actually think Mou Mou was my favourite ep and I don’t normally enjoy the ones that focus away from the main plot lines - I thought it gave an interesting background into how the Al Fayeds became part of society, Mohammed’s desperation to be accepted and loved and why he seemed to feel a kinship with Diana. Which I assume sets the groundwork for Dodi and Diana which must be early next season.I can see the logic behind the fayed episode, but it was a little boring and killed the flow of the series. I don't think it was worth losing out on other royal stories on. It could have been covered in an episode next series when he turns on the family (he wasn't exactly an angel either, plus there was no real reason he would be welcomed into the fold as just another rich businessman, the whole point is money shouldn't buy you access ).
I really enjoyed the scenes with Charles and Diana in the last episode. No spoilers, but while I assume it’s an entirely fictional encounter it was very well scripted and acted.