Hey all- I've been talking alot about these CPD25 events I go to, so here is the link for the website- check it out. http://www.cpd25.ac.uk/
CPD25 is related to CILIP, although I don't believe you have to be a member of CILIP to go on the visits. It is an organisation promoting professional developement for academic library staff members within the M25.
I went on a visit to Westminster School Library last December which was fantastic. I'm also booked on to their visit to the British Film Institute's Library on March 11th and to the Tate Library and Archives on April 16th.
I don't receive email about their visits automatically, the Librarian forwards them to me, so my advice would be to contact CPD25's base at the LSE directly to ask what you need to do to get on their mailing list.
I would recommend checking it out!