Hello! HQ here. Suspect the journalist chose a particular angle for that piece. Justine does mention Gransnet in many interviews and talks - wherever there is an opportunity in fact. Feel free to do the same - whichever universe you're in.
There is a big article on the media page of the i today. An interview with the lady who founded Mumsnet and Gransnet. The whole article - and there is a lot of it, is all about mumsnet. No mention of Gransnet at all