After searching around a bit, it seems from advice on other questions such as this that as long as we have letters from the other people in the flat and the landlady saying they are happy for us to live their together, as well as a letter from me describing the living arrangements (I have a room of my own, quite large, and share bathroom and kitchen) to the extent the officers will understand we're not packing twelve to a room, and also emphasising that it is a temporary situation while we find our own place, it should be fine? Way to go answer my own question. Anyone care to confirm?