I've started getting a message on the DIS at ignition, stating "Service in 5700MI 24 Days" I've done just 6800 so that sounds fine to me. But what's the 24 days all about? It started off at 28 (that I noticed) ans has gone down to 24 in the last 3 days. Car just 13 months old, so a bit confused. The manual mentions nothing about a DIS message (that I can find) and just states I'll see a spanner icon in the digital display in the speedo?