I've just had this problem on a '98 Alhambra. There is a 15A blade fuse underneath the drivers seat. I had to look right into the compartment with a torch to spot it. Lying on my stomach, in the back of the car (looking under into the compartment under the drivers seat, there is a single black fuse holder on the right hand side). Replaced the fuse and the 12V sockets in the luggage compartment came back to life! Another job to cross off the never-ending list on held to the fridge door with a magnet.