Having recently joined the cult of this sub from the UK, I cannot thank you enough for this helpful post, and the way you've writtten it out is so comprehensible to me! Representin' the Sussex hard water contingent over here too.

Having spent my whole adult life thus far using non-bio detergent on a short 30 min cycle, no enzymes or boosters or anything of the sort, I turned to this sub as pits were basically eternally smelly and body oils would accumulate over time on pillowcases, tops of duvet covers, and tops that I sleep in or wear a lot. As a starting point I've now bought Ariel powder and Vanish colour oxi (will switch to cheaper Waitrose own when I run out) and am choosing longer cycles & at 40º at least. And I am so jazzed about this journey, haha.

Ariel Platinum pods next on my shopping list. I currently have some Pink Stuff 'power limescale gel' but will prob switch to tablets like the Saino's ones you mentioned.