The National Film Theatre is indeed an alternative/old name for the BFI Southbank cinema, http://www.bfi.org.uk/whatson/bfi_southbank
. You can pick programs up from there and likely from other associated places. If you are a member they post these to you, I do not know if there is another way to receive it. There is a bi-annual Anime Weekend there where they show several Anime and Manga related films. For instance two years ago they screened 5cm Per Second and had a discussion and Q&A with the director Shinkai. According to the May program released today, this year the event takes place on the weekend of the May 21st. All the films are shown on their own (there is no all-nighter type arrangement). Beginning with Eva 1 and 2 of Friday the 21st at 18.30 and 20.45, joint tickets can be purchased at a lower price. Then on Saturday the 22nd is Stormy Night at 15.00, Welcome to the Space Show at 17.30, and Summer Wars 20.40. On Sunday the 23rd is Professor Layton and the Eternal Diva at 15.30, Chocolate Underground at 18.10, and K20: The Fiend with 20 Faces at 20.10. Both Stormy Night and Professor Layton have a reduced price for children of £1. Ticket prices for each film vary depending on age and such between 5 and 10 pounds. Unless they change, all the films are showing in NFT1 which is a large auditorium with a big screen and large seats, you can't eat in the show and they are fairly strict on performance rules. Champions members can book on April 5th, normal members on the 6th and public on the 13th, all at 11.30 am. Based on the two shows I went to last time, the event is popular but not overwhelmingly so, unless they are moved to a smaller screen (NFT2/3/Studio), I think it is unlikely to sell out quickly, though I might be wrong. Like the Sci-Fi all-nighter they gave some goody bags and free gifts the last 2 times, but that was likely only luck. I imagine there will be more information available on the BFI website before booking opens in a couple of weeks.
That's everything I can think of.
Personally I am not interested in Fate-Stay Night and the Bleach movies, but Redline and Musashi look good and I'm crossing fingers for a fifth film. So am on the fence about attending this all-nighter, though I do feel the atmosphere/experience makes up for any bad films. From the BFI weekend I will certainly be aiming for Eva 2 and Summer Wars, as well as Space Show too.