Just adding to this thread as this happened to me today:
2 weeks ago, I took the van for a 50min drive, came back home to take a phone call and in the 10 mins between turning the van off and getting back in it, it wouldn't start. It didn't even try to turn over. Did all the usual checks, nothing showed other than the battery being 10 years old. I left it sitting on the drive for a few days, went to check it again and it started up without a hesitation. Took it to Halfords today for a free battery health check to make sure I hadn't missed anything and they confirmed that the battery and alternator were both in excellent health.
Confident it was just a one-off, I decided to go shopping on the way home but when I went to start the van in Tesco car park, nothing happened. Just a dull "thunk". I tried jumpstarting it with the help of a lovely chap in the hopes that it was just a battery issue which had occurred in the 30mins since Halfords had said all was well. Surprisingly that didn't work so called the AA who turned up and came to the conclusion that it was the starter. We spent 10mins whacking it with a breaker bar and a hammer but ended up having to bump start it so it's currently at my mechanic's getting a new starter fitted.
For reference, the van is a 63 plate (2013) with 117000 miles on it, having just completed a 2000 mile round-trip to the South of France.