Leo eventually became ICL, I worked for them (ICL) on LEO III-26 at Charles House in London on payroll and utility billing, my experience was on Ampex TM2's & 4's which the Leo's uesd. The "scope" was on the engineers panel and was for monitoring the memory, it displayed as blocks of 4 bits - 0000 0000 0000 - forget how many coloumns, in a strange variant of hexadecimal, but the days before hexadecimal became the norm. There is an interesting website for LEO's at - http://www.leo-computers.org.uk/pageone.htm - including all the installations.