I have a feeling that the DM are busy going through trustees social media accounts.
I'd imagine the journalists (DM, TG, TT at least) doing the digging already dug, some time ago. Wasn't the full list of Mermaids-affiliated people, available in July? Or the summer at some point. It's a fair amount of time to have had, to search and go through what's in the public domain.
Whatever mumsnetters have been able to find eg that photo surely can't be all of it.
It feels like Mermaids are in that situation where something is revealed but that's not the full story because the press keep coming back with a new revelation each time.