Leaking mixer tap in kitchen unit?

I have a mixer tap unit, which leaks through the 2 x body swivels, I have dismantled the system and taken the cartridge to a plumbing supplies store, they say I have to find the maker of the tap, OK on further investigation I find that even with the water supply to the tap is off, it still leaks through the swivel/gland, what can I do to fix it, do I need to replace the 2 x valves at the end of the flexy hose to both outlets.