Visited two different suppliers to the electrical trade and although both had very helpful staff and I'd brought with me an example of a snap lock connector (which to my great surprise, none of the staff at either store had seen before) they could not help me. They did not stock single core wire thick enough to be held securely by the connector.
I think I'll phone a model railway store in the UK somewhere and see what they come up with.
In the mean time, I decided to switch my attention to another aspect of building a layout, namely, "clearance". A full-length train can rub against or foul trains on adjacent tracks and platforms.
So, in order to start exploring this issue, I laid down a dummy platform of the correct dimensions and set up a full-length train beside it. How far away should track be from the platform, from adjacent track etc etc?
Beyond setting up one dummy platform and one train, I did nothing else. Will pursue matters further in the following days.
Didn't listen to any music today beyond being irritated by that played on Radio 3's breakfast show: it's hardly better than "light music" or "easy-listening music" that they play at that time in the morning.