Progress!
I'm really busy with work at the moment, but got some time yesterday evening to tinker. First up, I sprayed more penetrating oil into the bores, then tried cranking it again. Back and forth, back and forth and then, yes, it turned! So now the engine turns all the way.
Then I connected up a battery and slowly but surely, the electrics crept into life. It was a bit odd, as at first, nothing worked at all, but then the headlamps came on, then one rear sidelight, then the wiper was working, then another rear sidelight and the fronts! Indicators don't work yet, but that's trivial at this stage.
I then, with the plugs out, bravely tried the Dynastart. It clicked, but no action. So, off with the top engine cover, gave the Dynastart a few 'love taps' with a hammer, and bingo! It is now turning the engine. That was at just after 10pm last night, so for the sake of the neighbours, I downed tools. Hoping to get a chance to try and get her running today!
Not sure what to do with the spares car yet. One thing at a time!