I guess I owe you all an update. I haven't had time to look at the car for a couple of weeks, but managed to get home early today so I started from scratch again.
With the scope attached to the crank sensor's connector, with a bit of knob twirling it showed the following trace.

I have absolutely no idea what that represents, but when I cranked the engine, the trace changed to this ...

I don't know what that means either, but at least it showed that there was some action in the sensor circuit.
Bouyed by this, I moved the scope probes to the ECU end of the harness and got exactly the same trace.
So far so good!
Next step was to reconnect the ECU and try a tooth log again. Bugger me, it was a perfect log.
Then I tried test modes for spark and fuel and I could hear coils firing and injectors working exactly as they should.
Well the only step left now was to actually try and start the engine.
Sorry guys, it's getting late and I have an early start tomorrow, so I'll finish this tomorrow.