I was thinking of upgrading my 760 to a 770 the other day and looked at Halfords site. The satnav is way cheaper on Amazon but I read their reviews and one chap said that there is a common problem with new 770s in that when you first update them after purchase they lose all of their campsite data bases. He is on his third unit and says Garmin are at a loss to explain the problem. Is this correct? Do you lose all the campsite info when you update?