Doyle has said in interviews that he wrote chunks of the novel in twenty minute gaps snatched during lunch breaks while he was still a teacher.
This helps explain why much of the writing has a sense of intensity and pressure, and possibly why it is written in episodes of varying lengths.
As the story is told in episodes from Paddy’s life as a ten-year-old, there is no real chronological order - or at least we are not aware of a chronological order.
All the detail seems to come from his ten-year-old perspective, but that is all the order we find.
The main thread of the developing problems between Mr and Mrs Clarke seems to develop chronologically as the novel progresses. But around this the events described could be from any time in Paddy’s young life.
There is one flashback. Paddy remembers a time when he was younger and created a fort under his kitchen table.
This seems to suggest an end to innocent carefree existence and the beginning of a time of conflict in the Clarke family. The flashback seems to be used to show that we look back for better times.
As the tension begins between his parents, perhaps Paddy is harking back to a simpler time. The fort in this memory could be symbolic, a representation of protection and safety from the problems of growing up.