what year is this truck?
assuming its basically the same as the US model
on older units with sol valves that fuse only feeds the FnR lever and the solenoids
the rev light is a switch

new units (late 90s)

it only powers the solenoids and the backup light relay coil (which is mounted to the inside of the dash cover) through the FnR lever
so since the relay is dead you get no reverse lights
the actual reverse lights are on the fuse thats second from the top
also the book lists the reverse bulbs as 10w

check the wires up to the FnR lever and the lever itself
does the lever have a small red tab that locks it in neutral?
also check for chaffed harnesses from the dash (green plug)