I've recently had to remove and refit my turbo a couple of times due to a warped flange. I polished it flat, fitted a nakatenga gasket and it seems to be fine but I went through 2 turbo oil feed pipes (LR031928 or Ford 6C1Q-6K679 DD) because the banjo bolt sheared. So, a couple of questions:

1) what is the correct torque for these? I was using 35Nm as per my workshop manual and I don't think my torque wrench is knackered.
2) does anyone know of a different banjo bolt and washers that would work? The copper washers on the bolt assembly are pre-formed such that you can't remove the bolt from the pipe - it's bought as an assembly. I now have 2 perfectly serviceable pipes that I can't use because I can't replace the bolts/washers.

I don't really want to experiment with this as the oil feed to the turbo is quite important... So, hopefully someone else has done it!

I had the exact same thing happen - sheered off the banjo bolt while attempting to torque to manual setting. Everyone I talked to said that was way too much torque for a banjo bolt. So, when I got the replacement, I just torqued it by hand and not that much - maybe 10 - 15 lbs? I have been keeping an eye on it - seems fine so far.