I don't know if you're still looking for an answer, but for people who look in the future, I'm at Aston right now, and getting summer accomodation as a first year has been very challenging, they don't reply to emails and when I go to the reception, I'm told they can't help, and I've had to run around all silly trying to get someone to helpe for months now, your best bet is emailing aston student homes, they will contact unite on your behalf and then you should be able to get accomodation to cover part of the summer