Snap, mine went off today also. I seem to remember seeing on another forum something about disconnecting the battery for a couple of minutes and it comes back to life. But I am worried about code on the raio being lost. So until I hear something positive I shan't worry about the mileage. It's already done 108,000 miles, so what the ****!! (51 Reg'd Diesel Comfort)
Otherwise a great car, I should have bought one years ago!
i found out it is probably the back bulb to odometer which needs changing, as i got a torch onto the odometer and could just see the mileage reading, this is with the power on. but it still meansthe dash needs removing to get to it. and battery has to come off as it may trip the airbag. luckly have the radio code in my service book, but if not this can be reset by vauxhall dealer. the only time you really need the mileage is to record on the mot. hope this helps, thanks