Quick update:
Coolermaster aerogate 1 arrived today and am running all the fans on minimum, much quieter than before, tho still a hum from the PSU fan
but i'm getting there!
Fan controllers are a great idea that i wish i'd have known about in the past!
I'm monitoring the CPU temp with Asus Probe to ensure the lower air flow doesn't cause any problems, but with my kind of PC usage it shouldn't be a problem.
Thanks to everyone for all your help
I'm definitely getting somewhere!
Cheers