Have you tried pulling on any of the existing wiring,if not this is your first job before quoting
Once you decide if they pull,the main problem may come with getting the supply from down below (if there is no pull)
You get the supply to a convenient light or switch,the landing being the only open area may very well be the best place to get that supply to lights/switches both above and below that floor
I would hazard a guess this is a simple singles rewiring through existing conduits,wall chasing and laminates destruction may end up being just an extreme solution
Take more care than normal before pricing,be sure exactly what you will be pricing for and any problems you uncover before the start
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Had a quick look in one rose and only 3 conduit wires connected,
How many actual pipes are at the light positions and switches