Ok... research done, with thanks to Tomcat for pointing me in the right direction.
A decent single blade 16" will pull >25% more air at a higher static pressure than a dual 12" set up.
The FFR supplied fan is a curved blade model, which is supposed to cut down noise.
After a couple of hours looking for a shroud or a new fan set up I decided to make my own cowling for the 16" fan, fitted body sealer rubbers to the edges and lined it with heat shield, in the hope it will attenuate some of the noise.
Fingers crossed I have a quieter, better performing fan set up...
If can advise on the fitment of the Vintage Air condenser to the front of the radiator that would be great. I received no instructions with it and didn't want to proceed unit I get info on the clearance / sealing etc, let alone how the brackets actually mount up..!
Cheers
Chris