dip/main is fed from the flasher switch, so make sure the wires from that to the fusebox are good. the solid white is main, solid yellow is dipped. you know headlight switch wiring is fine if main beam works, as the power feed from that feeds the flasher switch which then switches the output between them obv check both dipped beam fuses plus the bulbs are ok
ahhh there is the issue, the mk2 ignition loom had an additional yellow that went to the fusebox and the mk3 one didnt, we were going to replace it but forgot! that will be the feed we need