From my recent experience, you do not have to drill a hole to clean the evap core on VY (wish I posted this before hand...sorry davidnasd). All I did was remove the blower motor resistor and I could get in there with my phone to take photos and also a trigger nozzle hose to clean it all out. Occasional pic to see how well the cleaning was going. Worked a treat. All the wet grit came out through the air con drain hole.
This might be a daft question but are we only meant to clean the left side of the evap core? (EDIT: There are 2 sides to a core but only the left side is visible and accessible. I don't mean just half of the left side lol)
Our VY air con is pretty much all sorted now. Had some swollen seals on the compressor and the TX valve also had an issue. I guess this was because the air con wasn't used for about a year while the engine was out? Not sure. Anyway, thanks to the dye for showing the issue. New compressor, TX valve and dryer. Re gassed (another $130) and all good. Pulled the blower out again as it got a bit noisy but it's happy again now.
Full air con system doesn't seem to be at 100% like it was a few years ago. I'd grade it at maybe 70% of what it use to be. Is this common? Could this relate to only cleaning one side of the evap core? Blower motor runs fine and all ducts are clean.