Had a go at this topper thing.
It half worked. Took away the harshness but still loud. I guess at least now I don't really notice it over the fan and Air-Con. I tried to video for comparison, but on the recording they sound almost the same, so decieving. I assume it is because I created silence then the phone auto-level for mic kicked in to "help" lol
I might try with some background noise to see if it highlights the change.
It seems alot of noise still escapes the gearbox. I assume the mounting plate is acting like a speaker. I will probably try insulating it mechanically to see if there is any further significant improvement to be had.