As title, I've got a 2.0TDI (102) and as it is getting colder in the morning, I find it struggles to turn over for a second. Once the starter gets going, it starts fine, but I'm concerned it will get worse as we get into winter. My default would be replace the battery, but I did that last winter, I currently have a Exide EA640 battery which has a stated CCA of 640A. I don't think its a battery drain problem as it doesn't seem to matter if I have left the van for a day or a week. Any suggestions on where to start diagnosis?