Well, that came as a surprise...
I turned on the Dell Inspiron and it started to download the latest updates to the OS. It was on the dining table and I let it run as this operation seems to kill the machine, making it impossible to do anything else.
Returning an hour or so later, after taking Reggie (the dog!) for a walk, and it was about 25% the way through installing Windows 10. That was yesterday.
I know I had requested this "free" upgrade some months ago, but I thought I had the ultimate control on when I wanted to run it. I let it run as it seemed the lesser of two evils rather than cancel it.
Sadly, my first inclination may have been the right one as over the next twelve hours it installed and welcomed me to Windows 10.
I then logged in and after a few minutes the desktop disappeared and this was it. Just the weather widget!
No toolbar and no "start|" button. The only way I could get the desktop back was to restart the laptop. Not ideal. Then it cleared off after a few minutes.