If they have assets of under £250k then the law of intestacy determines that their estate passes to their spouse (assuming they're married) and then on to their dependents. Given this they might not actually need a will.
Interestingly, if we both die at the same time, the solicitor reckoned it would all go to her family as she is younger than me and it is therefore presumed she would have outlived me? Bizarre.
although how the executors can see into the future to confirm this would have been the case in a specific instance is indeed baffling.