Wow some astonishing links and pictures and other info in these posts.
I too was sad to hear of his passing, other than the C5 disaster, much of his stuff was quite good for the price.
I was already an Assembler Programmer in 1980, on 8-bit processors, Intel 8080/85, then a strange beastie called the RCA 1802, then the fabulous MOS TEC / Rockwell 6502.
Until I started on the 6502, I thought the 8080/85 was the best, until someone told me that registers aren't everything, addressing-modes are king. He was right. I could do far more, in less code, on the 6502 than on the 8080/85.
I had an Acorn Atom at home in 1984, that used the 6502 and was amazing. I never went further at home because I ended up on other projects in companies using the Apple IIe (6502) and the IBM PC (8085).
So (fortunately) I totally skipped the BBC micro (6502) and (lamentably) the ZX Spectrum (Zilog / Mostek Z80 CPU). From what I knew at the time, the Z80 CPU was an improvement on the (relatively rubbish) Intel 8085 with addressing modes comparable with the 6502.
If you never saw it, watch "Micro Men"
Micro Men - Wikipedia about the rivalry between Sir Clive Sinclair (played by Alexander Armstrong), who developed the ZX Spectrum, and Chris Curry (played by Martin Freeman), the man behind the BBC Micro. It's on youtube.
But 16 bit came along and it all accelerated with C programming etc, so quickly, so that Assembler Programming became a thing of the past
Anyway, I did actually purchase a Sinclair Product in 1977 - the Sinclair Cambridge Programmable calculator, which was brilliant, and it still works. My picture of my very calculator, on the fabulous book of programmes you could put into it.