Hey Dunney, I feel your pain (especially in the knees!)
The only good thing about it is that, having removed and fitted the oil tank about 5 times in the last few days, I can now do it in a few minutes. A really annoying thing about this banjo connection is that the oil tank threaded pipe is relieved to a smaller diameter after the threaded section, so whatever sealing washer (on top of the banjo) you use has to go over the thread, but when it gets down to the smaller diameter relieved section it can just move sideways and float about. As you tighten the nut that holds it, the washer easily gets pushed aside and misaligned, potentially causing a big leak. I ended up assembling it all on the bench using sealant and a 'false' nut to hold the washer tight, leaving it overnight to allow the sealant to harden, this way I could make sure the washer didn't shift. Next morning I undid the false nut, fitted the tank and connected the lines without the sealing washer moving.
So why, oh why did they machine that relieved section into the pipe, what's the point?