London Dairy has long been one of the first eateries to close on days that aren't projected to hit huge numbers. It honestly wouldn't surprise me at all if they just opted to make it a peak-only facility or even just close it down all together. Definitely something to keep an eye on regardless. Thanks for the heads-up!
It was open on Saturday the 28th when I was there as I stopped in an got an ice cream cone there. However it only opened at like 2pm (if I remember correctly) as I was one of the first persons to walk in.
Year-end report: I saw London Dairy open once the entire summer (and Halloween): pretty late on a Thursday night. It wasn't open when we arrived at the park that day, and it wasn't open any other days that I saw.