Re: I hope there is more than this somewhere
I also have a copy and knew one of the people who worked on EDSAC, which the LEO was based on. Unfortunately, at the time (1968/69) I'd never heard of EDSAC.
If you're interested in computing history then, alongside "A computer called LEO", your library needs a copy of "A Brief History of the Future" by John Naughton, which described the history of the Internet. Again, I've met one of the people involved, this time Roger Scantlebury, in 1984 at Logica.