I can recommend Superdry, they have a good selection of good Autumn/winter jumpers and really reasonable prices. I bought a couple last winter and lived in them, so comfy and still look brand new. If you order online they do free returns or drop back to any store.
I've bought a few items from them recently (simple basics not the funky stuff for youngsters 😂) and been really impressed.
Hope you find 'your jumper', they are a game changer.