Ashby Computers & Graphics Ltd. Also known as "Ultimate Play The Game"
Ah! Got it. Here's a few links for other clueless types like me. I grew up with the C64 in the US, but am mostly unfamiliar with the ZX Spectrum and BBC Micro. I love your other pico8 arcade adaptations though, and I'm looking forward to checking this out too (and maybe the original via emulation to compare). :)
https://www.mobygames.com/company/41150/ashby-computers-and-graphics-limited/
https://www.mobygames.com/game/14606/atic-atac/