Hmm, perhaps a solution would be before installation, to weld a short bar of steel between the lock nut and the 6mm Banjo bolt nut?I had a similar problem once. Solution was to MIG-weld pairs of nuts either side of a spacer so that each stopped the other from turning. Sprayed over the weld with cold galv afterwards. You could weld or braze them all to a spine if you could get it in as a single piece. More risk of them not lining up with the holes in the DB though.
It's such a shame you're not an apprentice - this would have been the perfect opportunity to tell you the tool you need is a 'reach around' and to head to the hardware store immediately to demand one
Feel free to hit that 'old' rating...
Well done though - amazing what's possible when you finally decide you've had enough and it's going to go together no matter how much of a fight it puts up!
Careful with the pxyz takes, after all, you're just a glorified plumber!![]()