Just started the RGS for the first time and noticed oil leaking from the oil tank return banjo. As usual the problem was traced to pattern parts. The new banjo was made with the smaller diameter hole too small so it wouldn't fit over the plain section of the pipe which is brazed onto the tank. Consequently, no matter how tight the nut was tightened, the fibre washer at the back of the banjo wouldn't crush against the tank. So, I've opened the small diameter hole on the lathe so that it's a snug fit over the plain section of pipe. I also noticed that the whole banjo is too deep so that, when fitted, the narrow diameter doesn't quite reach to fit over the plain section of pipe, so I've skimmed about 1.5 mm off the back face. Now, when fitted, there is a natural recess which can be filled with an O ring in addition to the fibre washer. Everything seems secure now and I see no reason why this shouldn't fix the problem.