Anyway….back to my original issue.
I managed to get my hands on 2 M6 copper washers over the weekend, but still no good. Then I tried using the banjo bolt and washers from the front brake (which works fine), but still no good (luckily the front brake is still ok when I reinstalled).
So, I’m left thinking that it must be an issue with the calliper or the actual banjo. I guess I could have cross threaded the banjo bolt into the calliper, but then again, I’ve never undone it before.
I’m going to try a bit more filing, and maybe some plumbers tape around the bolt. But to be honest, I can get a new calliper for $50, so not sure how much effort to put into this…