The banjo connection next to the end of the internal leak off line is for the pipe to the fuel tank, it goes through the firewall in the hole visible top left of the pic, connecting to the tank with an olive connection. Here's Billy's one:
Sandy
If it's blanked off at the fuel tank there will be no leaking out of the tank to spite the pipe not being there and a bit out of the banjo, if the banjo is plugged however, the build up of fuel could either leak into the engine oil or affect the injector opening pressure, the tank will also leak a bit. So you should really get this working properly again to be on the safe side, not too diffivult to do that.
Sandy