If you want to remain spoiler free don't click here, there be plungers!
http://ehyfpw.blu.livefilestore.com/y1px6Dm1RUN81xoH7OArg0_ZbrpUY7kbeNhRgfaLbP3e2T-6-l19jWqutFEOTdnHu4NZazHO9edsamB8z1mvthR-v_38_fkiion/mainImage%20montage.jpg
The BBC Archive has released some interesting documents about the show:
http://www.bbc.co.uk/archive/changingwho/10302.shtml