Something to do with the refurbishment was my guess as well. I really wanted to get something booked but now I don't know whether to wait or book a second choice just in case things start filling up.
Assuming that we're all going to eventually need boosters, will each person need to get a booster specific to the original vaccine they received? For example, since I got the J&J do all of my future boosters need to come from J&J?