Most reading weeks are development space so that you can take part in course relevant activities.
An example would be a week of short courses or trips all scheduled over a week from which you are expected to choose a full week's choice.
Generally being absent is regarded as a no no
I didn't know unis did reading weeks, only colleges. Is this where there are no lectures/classes and you are supposed to read up and catch up on things yourself? [my son and his friends just lie in bed till late and doss about all week ] !!