Had a look at the tail light wiring and removed some of the clutter. Replaced the connectors with soldering and the funky tape insulation with heat shrink. I can’t believe how much tape and connectors came off. Even though I’d already taken out a lot of unnecessary wiring while taking this kit off the bike in fall.
The lights themselves are mounted equally dodgily to the tail plate as the wiring was carried out so I’ll have a look at that too later.