I don't really see the point of insulating an extractor duct. It will reduce the condensation but won't eliminate it, so you'll still need a condensate trap anyway. But if you have a trap then there's no need for insulation.
Rigid ducting and a condensate trap would be my preference. I managed to sneak my outlet pipe through the fascia into the gutter, but if it drips onto the ground that's probably not a big deal.
This the one I've used, works well...
It needs to be as close as possible to the top of the ceiling, while having enough height for the liquid to run somewhere under gravity. May need a little compromise. Uses standard dirt cheap 22mm toilet overflow pipe. The short length of duct below it would normally be surrounded by loft insulation anyway, so no need for insulated ducting.
Obviously you shouldn't have any low spots, as the current botch job has. That will gradually fill with water with nowhere to go. All ducting needs to flow into the trap.
Rigid ducting and a condensate trap would be my preference. I managed to sneak my outlet pipe through the fascia into the gutter, but if it drips onto the ground that's probably not a big deal.
This the one I've used, works well...
Extractor Fan Condensation Trap With Overflow
Fit this Verplas extractor fan condensation trap into the ducting on the exit side of an extractor fan to capture any moisture running down the inside of the duct. It’s just the thing to prevent water caused by condensation collecting and causing a dripping fan or damp patches in the ceiling.The...
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It needs to be as close as possible to the top of the ceiling, while having enough height for the liquid to run somewhere under gravity. May need a little compromise. Uses standard dirt cheap 22mm toilet overflow pipe. The short length of duct below it would normally be surrounded by loft insulation anyway, so no need for insulated ducting.
Obviously you shouldn't have any low spots, as the current botch job has. That will gradually fill with water with nowhere to go. All ducting needs to flow into the trap.