Steering wheel off.
Strip the scuttle. Bonnet off will help access later.
Strip the centre console, carpets, kick panels, lower dash panels and a pillar trim.
Unplug the wiring at the at the a pillar bases.
Strip central dash panel.
Strip the steering column.
Cluster, glove boxes and air vents out.
Undo and remove all the bolts you can see and lift the dash out.
Heater box out with fan.
Unclip all the wiring as you go and feed the engine bay side back into the car... Should be one engine ecu plug and two of the round plugs. There's also a connector underneath the battery.
Might also be a bunch of wiring on the drivers side, some of which will involve stripping the wheel arches and bumper.
Obviously how much you strip off depends on what is required and on the car spec...
But work on the basis that the the loom went into the car after paint and before everything else and you'll be fine. And cutting stuff rather than taking time to carefully remove it probably won't be well received.