AdBlue?
I filled the Adblue tank a week before we set off for France in September. I guess it was technically overfilled as it was right up the filler pipe. I have been wondering why the low level light hasn't appeared on the dash. Rather than wait for it I put the four litres of Adblue I had been carrying in the boot in case it needed it. When we were in Spain earlier in the year the light came on twice. Both times I filled with 5 litre containers bought in fuel stations. Hence why I was a little concerned that the light hadn't lit up. Checking the odometer with 22153 on the clock or 1469 miles since it was full in September.