Lectures are not compulsory, neither in writing nor in practice.
You won't have any exams between May 8th - 15th; for first years they are generally quite early, but not starting before around the 25th at earliest.
As far as contact hours go, by this point in English Lit (and most arts subjects) lectures and seminars will be revision sessions, seminars for which don't tend to be registered. You may even not have any at all. A lot of students go home during this period as they find it easier to revise there, so you going to a week-long convention wouldn't be any different to that.