We've had five minutes to catch-up with everyone involved and we wanted to fill you all in on a bit of background.
We've been working on this latest version of the new mobile talk prototype for 6m+.
We've tried to replicate the commonly needed functions from desktop talk and address the current issues people had.
Part of our motivation is to be accessible and appealing to new and unfamiliar users while still be engaging and as usable as possible to existing users.
We tracked and looked at how users were currently using talk mobile and saw which features were well used and which weren't. We used that in part to inform which features to put front and centre and which could bear to be a click or two away.
We also considered those facts in light of different user groups (lurkers, new users, regular posters for example).
We have over the last six months tested with various types of users at several different stages. We watch users using various prototypes and listened to unfamiliar users, regs and lurkers feedback and we still are.
We tested every iteration both internally and with users. Over the last four rounds of testing around 80 mumsnetters and non-mumsnetters have participated. HUGE thank you to them, their feedback was and is invaluable. 
Hands up we did not specifically set out to recruit users with accessibility challenges and that's something we will absolutely rectify in future. We did refer to many guidelines out there to inform us of best practice but nothing beats asking real people so we'll definitely make sure we do better on that front in future.
We're still iterating and ALWAYS need more people who don't mind testing. It's particularly hard to get a good range of people who don't necessarily post much.
Please do keep all comments and feedback coming.