Well I won’t be staying at Queens College for the conference after all.
The online system mucked up my booking, as I indicated earlier. But it took two days to get any kind of response to my email of enquiry — no phone number on the website –, and by the time I decided just to make a duplicate booking and sort out refunds later, all but a tiny amount of the accomodation had gone.
If there are no more glitches, I shall be in Christ Church, it seems, in accomodation of a rather lower grade than I am comfortable with.