Thank you for the information, vadio, but it appears this has come into effect in the last six months or so, so your experience may not be indicative of the situation now, in the absence of evidence to the contrary.
In the meantime, I'm happy to say that the statements were sufficient and as of today, I'm on my new civil partner visa. Now to start collecting evidence for the next FLR(M), and then, ILR (and citizenship hopefully!).
Thank you so much to everyone for their help. I'm a huge fan of all of you.