when baking vegan lemon drizzle cake, should the soya milk be sweetened or unsweetened, fresh or longlife?
I've never had a problem w/ the long-life stuff.  (the 'fresh' stuff is likely also long-life, but people think of it more like milk when they see it in the coolers).   I actually prefer the unchilled stuff, as it's available in smaller containers so less likely to go off if I don't use it all up in time.

Sweetened will be closer to the sweetness of cow's milk, which might make substitutions easier if you're converting a recipe yourself.  If you're working from a recipe that calls for soy milk, just go with your own preference.