Thanks to buggies (George) for being brave (?) enough to look at my flashing scope display!
I was hoping that someone with experience would look at the display and recognise what was going on, or at least to suggest what might be wrong.
When I return to this Project in a few weeks (I've other things to attend to) I'll certainly check all my connections paying particular attention to any possible floating inputs or missing grounds.
Just to reiterate that at my level of experience (!) it's never clear if problems such as this are associated with the circuit design, poor/missing connections, breadboard contacts or faulty test equipment e.g. ageing oscilloscopes.
That's one of the many reasons why this Forum is, for me at least, such a valuable resource.
