Ah, but what kind of mucking about?
A lot of our "mucking about" on the RM 380Zs and 480Zs at school had to be done strictly out of sight of the Computing Science teachers, who were co-opted from their own discipline of maths and generally very nervous about anything close to unveiling of the magic boards inside these machines, or attempting to connect anything to the back. Even the technology/electronics teacher wouldn't go anywhere near it. Still, messing about in machine code (assemblers? pah!) on this machine led me to an understanding and career path that BASIC and CESIL would never have reached.