Update...
I waited until one of the Apple Stores opened 2 weeks ago and arranged an appointment with the Genius Bar. On inspection they found that a handful of keys, plus the space bar, plus the key pad were malfunctioning from spec and immediately assigned the laptop for repair. Hurrah! Too busy in the store repair facility, so I was recommended to have it sent to the Apple Repair Depot, 7-10 days... I assumed that it would be done quicker and in the London area.
2 weeks later it arrived by courier from Ostrava in the very east of the Czech Republic! Hopefully the laptop had it's lateral flow tests going and coming. As the keyboard is now in-built to the top case, a whole new unit was installed, and the best bit is that I've got a brand new battery because the battery is welded to the underside of the top case! Result ;-)
Thankyou to whomever suggested I look. I was vaguely aware in the past, but had completely forgotten.