So...new banjo nut arrived today
and it’s the same, it has a tiny pin hole to restrict the fuel return, next step loosed all the injector pipes and advanced the pump timing by 2mm , tightened everything and started it up , usual puff of smoke , put a dead Leg on the throttle set at about 1500rpm and watched the smoke disappear 🎉
ran it at 1500rpm for about 30 minutes straight and didn’t miss a beat, virtually no smoke , I haven’t added the fuel treatment yet, I will wait until I get it on the road.