So, just a quick update.
Things are moving forward again on the dash. It's now bolted into a full cab. Steering clear of the defrost vents and heater box doesn't seem to be a problem at all. Fitting around the steering wheel nicely.
Trying to keep things as versatile as possible so that things can be customized to each individual as much as possible. Dash vents at this point may or may not be doable. We have some solid ideas but need to source some accompanying parts.
One thing that really becomes evident as soon as you sit in the sat behind the dash, SPACE and tons of it. The dash is far more compact then the factory counterpart. If you need legroom this is the way to go.