TD5 Fuel pressure regulator

Engine started shudderign a bit after each gear change so looked underneath and there's diesel coming from the area or the pressure regulator, though I can't actually see it. It's definitely coming from it though because the pipes above and below it are fine, muct just be an 'o'ring, but just wondering how do i get to it? and i assume the pressure is still built up so how do i release it in order to work on it?
cheers

When they leak its best to change the reg and its gasket,dont worry about the pressure - it dies off soon after the engine stops.Worst thing is getting at it,its much easier on a Defender.