Thanks Damien.

I have the old battery out of the van and put a multi meter across the terminals and it's reading 12.3 volts but fluctuating a bit. The common man, or someone without your knowledge in the field, would view that as a charged and healthy battery. I did, and ruled out the battery as a cause of my problem. It was the battery that was in the van when I bought it about 18 months ago, so before that I don't know it's history. The one I installed has been in a number of my cars (I rotate batteries a bit depending on what I'm driving) and I know it well so I don't think there will be any future issues, but jumper leads will now be in ALL my cars from now on.

I'm glad I didn't pull the starter out first!