Leisure DB counted 7,009 gyms in the UK in its State of the UK Fitness Industry Report 2024. Nearly all of them are selling the same hour of somebody's day, and the timetable is the thing being sold. We still open sites where it exists as a download, or as a screenshot of a spreadsheet, or not at all beyond a line telling people to ask at reception. None of those can be read one-handed, and none of them appear in a search.
The second leak is the price. Plenty of gyms hold the figure back for the tour, reasoning that a visit sells harder than a number does. Our experience is that this filters out the people who were never joining anyway and loses a share of the ones who were, because somebody comparing three gyms at midnight carries on to the two that answered the question.
Third is the address. A gym gets bought on how far it sits from a front door or a desk, and we still find sites with no map, no note about parking and nothing about which entrance works after six. That detail belongs on the page and in your Google Business Profile, worded the same way in both places so the two records agree.