I must confess I'm not aware of that one, but I'll be noting that for future reference
I had multiple options on the machine I used in Reading, the tap water (free) option was not chilled and didn't taste amazing. I didn't expect much else to be honest, I was just grateful to have the option. There were chilled water and filtered water options, which were not super expensive but I didn't try them.
That Refill scheme mentioned that some shops/cafes offer, I have to confess I've never used. Now I'm familiar with it, I'll have to try it some time. With the prices Starbucks charge, I won't mind asking for a refill with tap water into my bottle. I paid the best part of £4 for a medium black coffee yesterday, which was bordering on insane. I was super decaffeinated though, to the point of having to be willing to accept such an insane price. £3.73 to be exact, including a 5p takeaway cup charge. I'll be here all day discussing my displeasure in such crazy pricing, so I won't go there, and when I next visit I'll see about this Refill scheme and feed back on it!