I did the metal a couple of years ago and it made a big difference, but was not a complete solution. So this was extra to that.
In an idle moment with coffee in hand while admiring my work sorting out the sound quality (curing unwanted panel resonances in an otherwise excellent design) of a PA speaker I finally read the Silent Coat instructions!
In the paperwork that comes with Silent Coat it mentions trim-panel resonances, and sure enough if you tap the panels they are quite noisy, especially in the annoying upper frequencies.
Adding a bit of mass to some areas, and it does not need to be everywhere just the wider un-braced bits, drops the frequencies a lot, so now it is no longer similar to tyre or wind noise. I’ll take them off again to add the foamy stuff I mentioned and post some photos later today.
EDIT.
Added some pictures showing patchy and untidy mass-deadening and sound absorbing foamy stuff added to trim etc.
However it does not matter if it is untidy so long as it works and fasteners etc are all accessible. Tidy is more likely to resonate!.
Driver’s side vent
Driver’s side trim
Passenger side vent and wiring clutter (I did remember later to click home again the filler release cable)
Passenger side trim
Too wet to go out today for a test and I’m waiting on a delivery. I don’t envy the poor driver his job.