I saw this film for the first time today and it is brilliant! It is so funny. And I was privileged enough to see it on the big screen with an audience so I saw it as a shared experience (which is how, in my humble opinion, films should be seen).
I loved Christopher Lee as Mycroft - in fact, I think he has gone right to the top of my list as my favourite Mycroft of all time. He really embodied for me the British establishment and the Civil/Secret Service of the day (and now for that matter! - move over Sir Humphrey!).
Quite a decent length Q&A followed the screening with BOTH Mark Gatiss AND Steven Moffat (yes Steven came too, and Sue, and Ian!). I took notes and I will do a write-up as and when I get the time (I am very conscious that I have yet to write-up the Nick Hytner talk at the V&A). I know that there is more interest in the Mark and Steven talk, and very few people could come to the screening and the Q&A as it is a small cinema, so I will prioritise this write-up (no promises though!).