There are may ways to do sausage, some fresh, some aged/cured, some smoked...it all depends on what you're looking for.
Has the BBC got it wrong, or the Chef that penned it? It seems to be missing a couple of things for a dry aged chorizo, but for a fresh Mexican style chorizo, as CraigC suggested I think it'd be fine for making fresh.
Curing salt is mainly to preserve the color so the amount of salt in here could potentially be ok for a cured chorizo but of you don't have a lot of experience with charcuterie I'd read up on it and look at some more specific charcuterie-centric places.
That depends on which salt cure you are using, #1 or #2.
Cure #1 is for quick cure/fresh sausage/meats that will be cooked, like fresh chorizo or even something that just cures a few days in the refrigerator and then is either frozen, smoked or cooked. Yes, it does preserve color via the sodium nitrite
Cure #2 is used for longer cured meats, like those that are hung for weeks/months. It has sodium nitrite, as well as sodium nitrate, giving it antimicrobial properties needed in long cures.
I'll answer for Craig. No, we would never cure something for 3 months that didn't have cure #2 in it. It would be cured a short time, a couple of days at most for something like chorizo, longer (about a week) for something like tasso that is a solid piece of pork, then smoked or frozen.
Charcuterie is not something you should take up on a whim. You have to have proper equipment and reliable recipes from experienced sources until you understand the complexities well enough to do it yourself. We still mostly use reliable recipes, but I have winged it a time or 2, though I used the basic formulas in regard to amounts of and which cures to use. We've dabbled in curing meats for 25+ years, back when you still had to get saltpeter and make your own curing salt. But, again, we used reliable recipes from experienced sources, especially back then, and still continue to research if we are trying something new.
Just a word of warning, keep your curing salts separate from regular salt. It's dyed pink to keep you from using it by mistake, but now lots of people are using Himalayan pink salt so you want to make sure things don't get confused. The curing salts, especially #2, can be toxic if used in too great of a quantity.
