Well this arvo I had a go at cleaning the evaporator. What a cuss of a job.
Out with the glove-box, then the blower fan and then removed as many of the screws in the bottom of the evaporator box as I could. I was able to get about a 2 inch gap around the front of the box to try and clean the internals.
Lots of crap in the blower fan so cleaned all that out and a fair amount of crap in the evaporator box as well. Gave it a vacuum the got into it with the garden hose and an airgun. I was also able to get the hose and airgun through the blower fan box, to access the evaporator.
Cleaned it up as best able then put it all back together. The aircon is certainly a bit cooler and there seems to be more airflow, though I guess this 3 hour home job wont be anywhere as good as a professional clean. At least I didn't have to get any re-gassing!
It isn't a particularly hard job, just awkward and potentially not worth the effort?
Would have been better had the system been designed with an in-line serviceable filter!