Day 1 - besides moving into a new house, I'll be buying a mobile phone/plan, and shopping for everything I'll need to subsist on in the near future. I already have a UK bank account left over from the last time. However, I don't like it much & have been thinking about changing banks. That won't be on the first day, since it's not high priority. First priority will probably be things like groceries, towels, sheets, pillows, and the like!!
In the next week after that is popping over to the uni to explore, see if anyone's at the Student Union yet (I'll be arriving a bit early before term starts), look into jobs there, buy a bank, and then decide if I want a job on campus or to waitress again (better money for the limit hours allowed by my visa).