Would anyone have any knowledge of the (sub?)-miniature cartridge fuses fitted inside voltage selector plugs used in some old British gear of the 1960's. Currently restoring my Rogers Cadet Mk.II ECL86 stereo amp, which has a 1 amp fuse. Much web searching has proved fruitless, except for noting these 'fused plugs' were also used in some Vox gear of the same period. The fuse measures 1/4 x 1/2".