DV has answered the question well. I would add that there can only be conjecture about the thickness of the insulation and the size of the gap in the vicinity of the V band clamp on XV230.
NG, I don't know, as a fact, what the temperature reduction is with a brand new insulation shroud. I've seen them, in good condition on other jets, and IMHO they are not designed to protect the equipment around a pipe with 400 C air pushed through it for hours on end. To be accurate, though, the engines are normally at about 90% while the SCP is used (duct air temp will be approx 300C). There will be an occasional increase to climb power (95%). When the pipe was originally designed it's sole purpose was for use as a crossfeed air start pipe. The SCP was then added with the introduction of MR2, then the empty refuel pipes (they were sucked empty before the days of AAR) in the area of the hot pipe were pressurised in flight during AAR. As aircrew, I unwittingly trusted other folk (engineering policymakers) to keep an eye on the the safety of all this.
As a matter of interest, we actually breath the air in that pipe and other similar ducts. There are no biological or chemical filters between the engine compressors and my lungs. Should there be a safety case for this???