I think (?) I have finally resolved one of the pieces I have been wrestling with for ages (having already gone down any number of dead-end routes). I have also jumped in with both feet to turn another experimental concept into reality. It's OK doing this - in fact I love it, except it can mean a waste of (sometimes expensive) materials if it doesn't work out. Both of these, especially the latter, are perfect examples of the idea incubating for months, but taking only moments to execute. Anyway, I'll find out soon enough if I'm happy with them. Or not.
I wrote the last part as soon as had got to the point where I needed to wait for paint to dry on the second piece, and I now have a feeling that it is going to be an 'or not'. Poo. I'll have another look in daylight tomorrow, and decide then.