I stripped the thread in the block but there was enough thread left that the banjo bolt would tighten up without the copper washers.
But it wouldn't make a seal and oil pissed out.
So a good mate of mine had someone make me a banjo bolt 3mm longer than standard.
(2 copper washers are 3mm when put together.)
Just put it in and all is good
I couldn't find a longer banjo bolt anywhere off the shelf.