but never even saw the hardware required.

There was none, 'The Little Operator' was software and ran on the PC. You needed to be 'trained' to use it. I fell short of paid lessons!

My dad had a Cavalier SRi. I think his was silver. Not seen one in a long time.

I looked mine up a few days ago on the DVLC site. I remember the plate number. It's currently not taxed, being a 'D' reg that's not surprising.