It's not that long. A quick scan does not support your assertion. Probably just as well, the quality of Clive's products left a lot to be desired. Best "built to a price" computer kit until the Pi Zero, though.
After learning to program on the local college (Merton Tech) mainframe (they allowed access to local schools), I bough a UK101 kit (Ohio Superboard 2, IIIRC) SBC around 1980. Luxury kit with 2K "Monitor" (OS), 8K Basic in ROM, 8K static RAM and 1K video memory. Program storage on cassette, 6502 processor running at 1MHz. Still got it somewhere.... though now with 32K dynamic RAM (again IIRC), 2K video (48 char x 32 lines), and RS232 with proper +/-5V switching and multiple baud rates. I'm not sure I'd risk switching it on -- chunky electrolytics now almost 40 years oldI (pre) ordered a ZX80 but it was going to take far too long than an impatient twenty-ger was prepared to wait so I cancelled it and got the OHIO Superboard 2 (Challenger II P) instead, I must have spent more hours programming than I spent playing Space invaders later..
Programing was a slim version of Basic, then Machine code could be used by poking data in to the Memory locations one at a time, there was no way back so any mistakes meant starting from the beginning... Grrr..
It still lives in my loft and worked at last outing a few years ago, much modified by now of course.
PS the kit cost £219 +vat!