Is it leaking near the washers? Are they forsure good copper crush washers?
In one instance, i used copper crush washers that had an inside diameter slightly too large. It leaked.
I have since ditched the rubbish banjo bolt setup (it sucks, they?re garbage metal if you got it cheap) and went to a m12x1.5>4an fitting. Wayyy better.
Here you go. Well with the switch in my opinion.
https://m.ebay.com/itm/AN-4-AN4-4AN-to-M12x1-5-Metric-Adapter-Black-/160487676730
(I?m assuming your feed is already 4an by the way, i didn?t read though)
I think it got hung up on the clampy dealy, already ordered one of what you linked.