RIP. Many a programming career, including mine, was started thanks to Sir Clive. There was a sense of wonder and awe around those machines that is no where to be found these days, even though we have so much power computational power. Something was lost.
Started with a ZX-81 clone. The factor I liked most was the attention with the manuals, they really cared to teach the basics of programming, even low-level things, to the layman.
I memorized the ZX81 (and Spectrum) manuals back to front. Around age 11 I used to write out assembly long-hand and "poke" the OpCodes into memory to write programs and drivers. I really credit what has now been a long and happy career in software development to the affordable computers Sir Clive developed. (My family was pretty poor growing up, but I convinced my Dad to spring the 80 pounds or so for one after I borrowed a friend's and took to it).
What you could do was limited enough that you could master it, and I really think that's a good thing for education and motivation. When I think about teaching my kids to program today, I effectively get "choice paralysis" from all the paths I could go down and the options within easy reach.