Following Hugh's comments on the call, I have checked in at the "special rate" at the Mama Shelter from Saturday 25th for 8 nights. According to the conference website, "special TEI discount rate" of 106 euro per night is available, but only until 2 september, i.e. tomorrow. However, the hotel's own website doesn't seem to know anything about this, and offered me 79 euros for some nights of my stay and 115 for others. Oh well. It looks dead posh anyway.