You really need to visit the National Media Museum in Bradford, unfortunately for you it's somewhere in the region of 200 miles away from London, but it is exactly what you want.
It's a shame it's not 1999, because then you could've visited MOMI before it closed, but seeing as time travel is not yet possible, I think that leaves you with a few alternatives.
It may perhaps be worth contacting the Science Museum to see if they'll have any related exhibitions timed for your visit to London.
You may do well to also enquire at both the LUX and the BFI may very well be able to assist you as well.
Thanks so much, yeah i went to MOMI as a kid and i loved it, remember the zoetropes and praxinoscopes there, i'll try out the science museum, I remember they had a exhibition on celebrating Pixars 20 Years, I missed that too.
Thanks for the help, I'll call around a bit and try to get some details
If anyone else knows of any exhibitions going on or any ideas they'd like to share, please do