Boost leak? Hissing under power.

[Alfashark]

Hi all, 2009 PD140 Superb II (BMP engine).  Pulled over to roll a smoke on the drive home from a weekend away and upon accelerating away from rest, a decent hiss started.  Pulled back over and had a quick look under the bonnet for any obvious issues like intake hoses blown off their couplings but everything seemed tight and intact. 

Continued on home with no warning lights on the dash, no smoke out the exhaust and didn't seem to be noticeably down on power - Just a hissing that increased in volume in proportion to the amount of throttle/boost at any given moment.

I've since undone the clips to the couplings on the hose just forward of the fuel filter and where it joins the silver alloy housing at the rear of the head (ASV/EGR?) and all appears to be well seated and sealed there.

On the left-hand side, after much swearing I managed to get my hand down between the air filter->turbo hose and have a feel around on the outlet hose from the turbo to the hard pipe and it feels somewhat softer than the hoses I previously mentioned - also, it's a red/orange colour... There may be a roughish patch on the underside of said hose, but even when I squeezed my camera down there it couldn't focus sharply enough to see.

What I can see when looking from the top, is what maybe a rubber sealing ring just visible below the joint of the hose and the turbo outlet.  From what I can feel, the metal clip is firmly in it's groove and I can't push the hose any further in to the joint.

 

Opinions and ideas would be greatly appreciated.