So the trip organizers finally got back to us with details on our options for accommodation.
We have four options. International Students House, two hotels, and a couple of self-contained flats. ISH is by far the cheapest option, and it's nice and central (Marylebone area), but accommodation is in triples, and there's no guarantee I'd be sharing with someone else from Guelph. This does not bode well, although ISH has by far the coolest facility.
The first hotel is in West Hampstead. It's the next cheapest price-wise, but a lot farther from the centre of town and the price doesn't include food (breakfast, yes, but nothing else). However, accommodation is in doubles and I'd definitely be sharing with someone from our own group, plus two people to a bathroom is a much nicer ratio than 10 or so! We don't know anything about the second hotel yet, other than that it's in the King's Cross area, so much more central.
Finally, we have the option of the flats. Much more expensive, food not included in the price (but there are cooking facilities), 4 people to a flat (2 per room), and very central, as well as very close to where our classes will be held.
I'm torn between the student residence and the hotel. I'd like to be staying somewhere central, and the student residence price can't be beat, but my introverted self cringes at the thought of sharing a small room with two people I've never met before and might not get along with (but then again, sharing a room with one person I barely know might suck equally). It's basically a toss-up between having more roommates but a nicer location, and a nicer facility but farther away from stuff.