It cost $30 to get the system degassed by an AC shop. They catch it in a little LPG bottle looking thing.
There is a little residual pressure in the system after they de-gas it. Don't be a complete retard like me and get under the car, and crack the first (and lowest

Removing the bits under the dash is very straight forward, after removing the glove box, you can see the AC gets its own compartment in the HVAC system. You just pull it out, remove the AC core (and leaves and other debris that are in there) put it back together, put some rape tape over the holes and put it all back together.




The only place i could find that had the larger of the two blanking grommets was clark rubber. It didnt look like automotive grade rubber (i assume there is such a thing) but i was provided "word of mouth assurance" from the bloke at clark rubber that it would be suitable for the application.