I took the car in to Gus at Alfatune in St Helens yesterday (it started first time cold without any Easy Start). He left it running for a couple of hours with no problems, then repeatedly started it with no problems.
He pulled the codes and there was a bad MAF, and a Crank Sensor out of sync. He did say the out of sync was fairly uncommon, but the Crank Sensor didn't have resistance to spec so replaced that.
He did say the glow plugs are probably on their way out, but the tip was to try the engine, if it doesn't start, turn it off, wait a couple of seconds, then try again. The diesel from the first attempt is still evaporating in the engine, and that it enough for it to start the second time.
Oh yeah, and the place I was spraying the Easy Start - A plastic shroud that goes to nothing! I was spraying it into the bit from right of the engine bay, where the air pipe seems to disappear into. So in my case, Easy Start was doing absolutely nothing, and I was in fact using the technique described above.
This morning it started first time.
Thanks for all the input and amusement.