Diesel hilux-fuel prob?

LN85R:-420xxxkm water trap filter draining back into tank overnight. flexible fuel lines replaced-no change. No obvious leaks. No spillage anywhere. Filter top not sealing, or inj. pump leak? Was running great at modest speeds. Sudden prob. Filter does drain fuel if tap opened & pumped. Drains too fast to walk around & start motor on the 'prime'. History of loose pump inlet banjo bolt-tho' seems tight now, not leaking with +ve pressure.