I think it is entirely appropriate to discuss Saving Labour on this thread because, as you say, Saving Labour (and Progress) are Labour groups opposing Corbyn, whereas Momentum is supporting him.
If insinuations are going to be made about Momentum, its founder and supporters, it seems to me to be quite fair that the secrecy, or otherwise, and conduct of other groups be examined also.
I'm sure Gransnetters are able to understand that, without becoming confused.
If my comment on this point is considered to be "derailing" the thread then I will be able to find many examples where similar "derailments" have occurred without any intervention being thought necessary.