Some discussion on mixed fiber and on PV, but didn't see any address of the OP's referenced kilt. The description
notes it is Teflon coated, which would make it good odds it is Marton Mills PV. PV is a mixed fiber in that it contains
polyester and viscose, or rayon, as we would say in the States. Hardwearing, easy to clean, less dear in the purchase
than wool. The referenced kilt is from bauhaus boy/Carse of Gowrie, several have reported good experience there.

Father Bill says better to save from scratch. I find the best way to save from scratch is to wear something between
you and the wool.

I have both wool and PV, like both. As for temperature, I have not worn my PVs out at temps below about 12 degrees
Fahrenheit, so I can't advise about cold weather wear. As I was not waiting an hour for a bus, or walking more than
a couple of blocks, I was OK in PV kilt and tee-shirt. Longer exposure at those or colder temps would seem to argue for wool. And probably a jacket. YMMV, and your expected usage is a factor.