Don't worry about reading before you actually come to Durham. There are some books you can read but departments vary in terms of rolling out a pre-reading list for general preparation. So you can ask some current English Lit students if they got one, and if they did, you will probably get one too. You can chat to them on UniBuddy: https://www.durham.ac.uk/study/student-connect/unibuddy-uk/.
In my case (law), we didn't get any official pre-reading list and were only told about our coursebooks on induction day. Everybody was freaking out but it turned out to be not a big deal later haha. Essential reading is generally available on Blackboard and titled Talis Aspire Reading List, so you can access that once the uni sends you your login details.