That is a good idea. Somehow tie it into the current IT curriculum to show school children the history of computing.
Also see if there are any project budgets available from the British museums.
Or sponsorships from one of the current big IT companies such as IBM, Sun, Nintendo, Sony, Microsoft etc... The console developers love such projects as a way to advertise their latest hardware. Also a great way to get free next gen hardware into the exhibition to show the latest in the history of the computer/gaming timeline.