Laguna II Mileometer reading suddenly zeroed and started again

Hi, I have a 54' Laguna II Extreme (from new) that has done around 156,000. Today, I've noticed the mileometer has zeroed itself and say's that I've done 23 miles! At first I thought I was on the trip page, but it's definitely lost it's true reading. Is there any way I can restore it without calling the garage?



Many thanks,

Andy