I invested in the SJS trunking which as you know has no internal foam.
As I do not live in a cold climate I have no need to take warm air from behind the radiator.
I have installed a short, 20 cm., trunking and have the original trunking mouthpiece which I believe is important for air entry flow.
I have no interior foam as there is no length to create or dampen noise and personally would not risk
having unknown foam inside the air duct, even with the air filter after it.
In my opinion the appearance is quite cute. Sorry no pictures, don´t know how.
I see no reason why this version should not work in the UK unless you want the absolutely maximum power and therefore need to site the trunking mouth in front of the radiators. People ask where is the rest of the elephant.
Dave the cog.