ΔH, Avon-powered Hunters were prone to engine surge when the guns were fired, due to ingestion of muzzle gases. The only solution was to 'dip' the fuel supplied to the engine whilst the guns were firing, which briefly reduced the fuel supply during the half second or so during which the trigger was pressed.
Probably only a problem if all 4 guns on the SS Hunters were fired together, but fitted to all Avon-powered Hunters nonetheless.
Hunters whose guns were no longer used clearly didn't need the system and many had it disconnected under mod 1321. But following the loss of XL597, there was concern that the rotting old wiring might still be capable of interfering with the engine fuel supply, so the design authority required that all components and wiring associated with gundip were to be removed.
Courtney Mil will probably remember the rusty old knobs and tits on the F-4 centre pedestal left over from mud-moving days, which we air defenders never used. Apart from one chap, that is, who moved something and lost his tanks, or similar. From then on, the edict was "Don't touch anything!" on the centre pedestal, apart from the centre station selector for the gun.
Leaving old wiring in jets is never a good idea!