Ok folks, i'm definitely up for a London Muppet Meet up!
Here's the info I managed to find, yes there's a screening at the BFI on the Embankment , which unfortunately, according to the link, is fully booked, but you can check back on the day for tickets -
http://www.bfi.org.uk/whatson/bfi_southbank/events/previews_in_conversation/loco_preview_the_muppets
And secondly, I spoke to the manager at the
EMPIRE cinema in Leicester Square, who said that they have the Premier for The Muppets because they're doing a promotional campaign leading up to the films release.
He also mentioned that due to the building work that's going on there, with most of Leicester Square closed off, the Premier might not be able to take place, but it's currently under discussion.
I'm not gonna take that as gospel, but he seemed fairly knowledgeable, and as per usual with Premiers, he said it would be invite only, but i'll certainly be keeping my ears open and doing everything I can to get a ticket.