I'm surprised you didn't mention the news item which made bigger public notice in the UK than the movie did: That the 43 year old director banged the lead actor Aaron Johnson and had his baby.

Which is progress I suppose, I mean remember when that was the other way around?

As for the movie, I'm intrigued to. I'm a sucker for those movies which primarily explore the origins of legends or larger-than-life figures before they entered myth and history. Lennon's own upbringing has material (and the of course the beginnings of that band) for an interesting picture.

Knowledge of that history certainly makes something like "Mother" much more painful.