if you find those washers to be a problem on saturday/sunday .... when you can't get a replacement put a piece of fine sandpaper on a flat surface and rub the washer against it with the flat of your finger, should leave a nice shiney surface with no black lines on it, as a bonus you get a lovely clean circle on your finger...
do both sides of both wasters and also the banjo bolt sides.
sounds like thats where the leak is coming from , unless the pipe has failed... hope its the washers, handy fix