One and a bit xmas jumpers later...

Superwash wool it ain't (it's King Cole Merino Anti-tickle superwash). Enough said - this ended up being my xmas jumper submission... :(

18-12-2018 Edit to add: I've raised my issues on Ravelry, and it turns out that it might actually be my washing machine shocking the yarn with cold water when it rinses (it has no hot water inlet). So it might well be operator error - I made a jumper in this yarn in October one year and had no issues, but the cold water is currently VERY cold here. Humph. Yet another swatch required! Pah...