It changed in the middle of last week. All the LHR T5 lounges now have switched over, including CCR and Flounge, so I think it's a permanent change. CCR staff are still getting the knack of pouring it (which seems to involve a very swift up-ending).

It comes from a different spring and does have a different taste to Highland Spring. The sparkling version is definitely fizzier. Highland Spring seems to go flat too quick.

Highland Spring actually comes from just north of Dublane, you can see the plant from the A9. Speyside is from the Cairngorms between Grantown-on-Spey and Huntly.