A final update to bring this thread to a close. Last week Mattermost were in touch and approved the license, apologised for the delay and thanked us for our patience. The next stage of the process was incredibly smooth and quick, from invoicing to providing the key all within around 72hrs.
My understanding is that our application may have arrived at a time of change and transition, where the non-profit workflow was under review, which resulted in unexpected delays and gaps in communication - so shouldn’t be seen as indicative of the normal non-profit application experience.
Mattermost is a great product and, once connected, the outreach from the Mattermost team has been really positive. Thank you.