This was an interesting read, thank you.
I have one methodological question: are the 98 group organisers that responded to the survey all from different groups? Or are a few of them from the same group, and if so, what does the data look like after correcting for this?
(I fear the data may over-represent bigger groups, as they'd have more members responding to the survey.)
EDIT: found it, from the 2017 survey report: "Where groups had more than one organiser, they were asked to nominate one organiser to complete the questions designated for organisers." So never mind, then!