Hi Colin,
The battery in my S type when I bought it was almost new and had the date written on it. It was 4 years and 11 months old when I changed it. The battery I got was a Platinum and only lasted 3 years and 4 months. It only had a two year warranty,
The battery that the AA fitted is a Bosch and is the battery that was marked as the one specified for the S Type Diesel. It also has a 5 year warranty, which gives me a bit of confidence.
Regards,
Peter.