Unless using grid sockets it seems odd to have two cables from the same socket going into the loft from a double socket, it may be that using a grid socket could help you, with a double grid socket (actually classed as 4 units as a socket takes 2 units) you actually have two independent sockets on the same plate, so you can take the ring from both sockets.
Also using a grid system you can have a switch, fuse, and socket in a 4 module plate so you could turn the loft supply into a fused spur and keep one wall socket so you do not need to run any new cables.