Rob, I can,t see any extra relief valve in the rail. The end with the DRV has a banjo fitting underneath, joined to the injector leak-off and tank return, and a clipped in pipe on top going to the HP pump. Ian, as you say, the leak-off test is relative,and by replacing one injector, I have moved the goal posts! Mark, e-mail on it's way, thanks for the interest shown, Peter