My wife has also an Hilltrek anorak (simple ventile) but without map pocket and kangaroo pocket (I prefer something ligther and compact). My son used it one week this winter in lappland until -15°C + 50 km/h wind.
He was nice on snowwalking with a woolpower 200 and a simple fleece from Regatta. Well protected and not damp from his sweet. For winter in Lappland, the hood could be cut deeper but it would not be very nice in mountains (seing upstairs). So, you need sometimes a brim cap to protect you more from snow.
Very nice scottish piece of gear.